Done, tested, too many options.

code/__DEFINES/misc.dm

@@ -530,3 +530,10 @@ GLOBAL_LIST_INIT(pda_reskins, list(PDA_SKIN_CLASSIC = 'icons/obj/pda.dmi', PDA_S
 #define SCAVENGING_SPAWN_MOUSE		"spawn_mouse"
 #define SCAVENGING_SPAWN_MICE		"spawn_mice"
 #define SCAVENGING_SPAWN_TOM		"spawn_tom_the_mouse"
+
+//Scavenging element defines for ckey/mind restrictions.
+#define NO_LOOT_RESTRICTION			0
+#define LOOT_RESTRICTION_MIND		1
+#define LOOT_RESTRICTION_CKEY		2
+#define LOOT_RESTRICTION_MIND_PILE	3 //limited to the current pile.
+#define LOOT_RESTRICTION_CKEY_PILE	4 //Idem

code/datums/elements/scavenging.dm

@@ -16,13 +16,17 @@
 	var/can_use_hands = TRUE  //bare handed scavenge time multiplier. If set to zero, only tools are usable.
 	var/list/tool_types //which tool types the player can use instead of scavenging by hand, associated value is their speed.
 	var/del_atom_on_depletion = FALSE //Will the atom be deleted when there is no loot left?
-	var/list/search_texts = list("searches through ", "search through ", "You hear rummaging...")
+	var/list/search_texts = list("starts searching through", "start searching through", "You hear rummaging...")
+	var/loot_restriction = NO_LOOT_RESTRICTION
+	var/maximum_loot_per_player = 1 //only relevant if there is a restriction.
+	var/list/scavenger_restriction_list //used for restrictions.
 
 	var/mean_loot_weight = 0
 	var/list/progress_per_atom = list() //seconds of ditched progress per atom, used to resume the work instead of starting over.
 	var/static/list/players_busy_scavenging = list() //players already busy scavenging.
 
-/datum/element/scavenging/Attach(atom/target, amount = 5, list/loot, list/unique, time = 10 SECONDS, hands = TRUE, list/tools, list/texts, del_deplete = FALSE)
+/datum/element/scavenging/Attach(atom/target, amount = 5, list/loot, list/unique, time = 12 SECONDS, hands = TRUE, list/tools, list/texts, \
+								del_deplete = FALSE, restriction = NO_LOOT_RESTRICTION, max_per_player = 1)
 	. = ..()
 	if(. == ELEMENT_INCOMPATIBLE || !length(loot) || !amount || !istype(target) || isarea(target))
 		return ELEMENT_INCOMPATIBLE
@@ -40,6 +44,8 @@
 	if(texts)
 		search_texts = texts
 	del_atom_on_depletion = del_deplete
+	loot_restriction = restriction
+	maximum_loot_per_player = max_per_player
 	if(can_use_hands)
 		RegisterSignal(target, list(COMSIG_ATOM_ATTACK_HAND, COMSIG_ATOM_ATTACK_PAW), .proc/scavenge_barehanded)
 	if(tool_types)
@@ -50,25 +56,25 @@
 	. = ..()
 	loot_left_per_atom -= target
 	progress_per_atom -= target
+	if(maximum_loot_per_player == LOOT_RESTRICTION_MIND_PILE || maximum_loot_per_player == LOOT_RESTRICTION_CKEY_PILE)
+		maximum_loot_per_player -= target
 	UnregisterSignal(target, list(COMSIG_ATOM_ATTACK_HAND, COMSIG_PARENT_ATTACKBY, COMSIG_PARENT_EXAMINE))
 
 /datum/element/scavenging/proc/on_examine(atom/source, mob/user, list/examine_list)
-	var/text
-	var/methods = tool_types
+	var/methods = tool_types.Copy()
 	if(can_use_hands)
-		if(!length(methods))
-			methods = list("bare handed")
-		else
-			methods += "simply bare handed"
-	text = english_list(methods, "", " or ")
-	. += "<span class='notice'>Looks like [source.p_they()] can be scavenged[length(tool_types) ? " with either a" : ""] [text]</span>"
+		methods += list("bare handed")
+	if(!length(methods))
+		return
+	var/text = english_list(methods, "", " or ")
+	examine_list += "<span class='notice'>Looks like [source.p_they()] can be scavenged [length(tool_types) ? "with" : ""][length(methods == 1) ? "" : "either "][length(tool_types) ? "a " : ""][text]</span>"
 
 /datum/element/scavenging/proc/scavenge_barehanded(atom/source, mob/user)
 	scavenge(source, user, 1)
 	return COMPONENT_NO_ATTACK_HAND
 
 /datum/element/scavenging/proc/scavenge_tool(atom/source, obj/item/I, mob/user, params)
-	if(user.a_intent == INTENT_HARM) //Robust trash disposal techniques!
+	if(user.a_intent == INTENT_HARM || !I.tool_behaviour) //Robust trash disposal techniques!
 		return
 	var/speed_multi = tool_types[I.tool_behaviour]
 	if(!speed_multi)
@@ -76,7 +82,10 @@
 	scavenge(source, user, speed_multi)
 	return COMPONENT_NO_AFTERATTACK
 
+/// This proc has to be asynced (cough cough, do_after) in order to return the comsig values in time to stop the attack chain.
 /datum/element/scavenging/proc/scavenge(atom/source, mob/user, speed_multi = 1)
+	set waitfor = FALSE
+
 	if(players_busy_scavenging[user])
 		return
 	players_busy_scavenging[user] = TRUE
@@ -84,37 +93,58 @@
 	var/len_messages = length(search_texts)
 	var/msg_first_person
 	if(len_messages >= 2)
-		msg_first_person = "<span class='notice'>You [progress_done ? "resume a ditched task and " : ""][search_texts[2]] [src].</span>"
+		msg_first_person = "<span class='notice'>You [progress_done ? ", resume a ditched task and " : ""][search_texts[2]] [source].</span>"
 	var/msg_blind
 	if(len_messages >= 3)
 		msg_blind = "<span class='italic'>[search_texts[3]]</span>"
-	user.visible_message("<span class='notice'>[user] [search_texts[1]] [src].</span>", msg_first_person, msg_blind)
-	if(do_after(user, scavenge_time, TRUE, source, TRUE, CALLBACK(src, .proc/set_progress, source, world.time), resume_time = progress_done))
+	user.visible_message("<span class='notice'>[user] [search_texts[1]] [source].</span>", msg_first_person, msg_blind)
+	if(do_after(user, scavenge_time * speed_multi, TRUE, source, TRUE, CALLBACK(src, .proc/set_progress, source, world.time), resume_time = progress_done * speed_multi))
 		spawn_loot(source, user)
 	players_busy_scavenging -= user
-	progress_per_atom -= source
 
 /datum/element/scavenging/proc/set_progress(atom/source, start_time)
 	progress_per_atom[source] = world.time - start_time
+	return TRUE
 
 /datum/element/scavenging/proc/spawn_loot(atom/source, mob/user)
+	progress_per_atom -= source
+
 	var/loot = pickweight(loot_table)
 	var/special = TRUE
 	var/free = FALSE
 	if(!loot_left_per_atom[source])
-		to_chat(user, "<span class='warning'>Looks likes there is nothing worth of interest left in [src] anymore, further attempts would be futile.</span>")
+		to_chat(user, "<span class='warning'>Looks likes there is nothing worth of interest left in [source], what a shame...</span>")
 		return
+
+	var/num_times = 0
+	switch(loot_restriction)
+		if(LOOT_RESTRICTION_MIND)
+			num_times = LAZYACCESS(scavenger_restriction_list, user.mind)
+		if(LOOT_RESTRICTION_CKEY)
+			num_times = LAZYACCESS(scavenger_restriction_list, user.ckey)
+		if(LOOT_RESTRICTION_MIND_PILE)
+			var/list/L = LAZYACCESS(scavenger_restriction_list, source)
+			if(L)
+				num_times = LAZYACCESS(L, user.mind)
+		if(LOOT_RESTRICTION_CKEY_PILE)
+			var/list/L = LAZYACCESS(scavenger_restriction_list, source)
+			if(L)
+				num_times = LAZYACCESS(L, user.ckey)
+	if(num_times >= maximum_loot_per_player)
+		to_chat(user, "<span class='warning'>You can't find anything else vaguely useful in [source].  Another set of eyes might, however.</span>")
+		return
+
 	switch(loot) // TODO: datumize these out.
 		if(SCAVENGING_FOUND_NOTHING)
 			to_chat(user, "<span class='notice'>You found nothing, better luck next time.</span>")
 			free = TRUE //doesn't consume the loot pile.
 		if(SCAVENGING_SPAWN_MOUSE)
 			var/nasty_rodent = pick("mouse", "rodent", "squeaky critter", "stupid pest", "annoying cable chewer", "nasty, ugly, evil, disease-ridden rodent")
-			to_chat(user, "<span class='notice'>You found something in [src]... no wait, that's just another [nasty_rodent].</span>")
+			to_chat(user, "<span class='notice'>You found something in [source]... no wait, that's just another [nasty_rodent].</span>")
 			new /mob/living/simple_animal/mouse(source.loc)
 		if(SCAVENGING_SPAWN_MICE)
 			user.visible_message("<span class='notice'>A small gang of mice emerges from [source].</span>", \
-				"<span class='notice'>You found something in [src]... no wait, that's just another- <b>no wait, that's a lot of damn mice.</b></span>")
+				"<span class='notice'>You found something in [source]... no wait, that's just another- <b>no wait, that's a lot of damn mice.</b></span>")
 			for(var/i in 1 to rand(4, 6))
 				new /mob/living/simple_animal/mouse(source.loc)
 		if(SCAVENGING_SPAWN_TOM)
@@ -122,7 +152,7 @@
 				to_chat(user, "<span class='notice'>You found nothing, better luck next time.</span>")
 				free = TRUE
 			else
-				to_chat(user, "<span class='notice'>You found something in [src]... no wait, that's Tom, the mouse! What is he doing here?</span>")
+				to_chat(user, "<span class='notice'>You found something in [source]... no wait, that's Tom, the mouse! What is he doing here?</span>")
 				new /mob/living/simple_animal/mouse/brown/Tom(source.loc)
 		else
 			special = FALSE
@@ -145,7 +175,7 @@
 				rarity_append = ". Nice."
 			if(20 to 50)
 				rarity_append = ". Not bad."
-		to_chat(user, "You found something in [src]... it's \a [A][rarity_append]")
+		to_chat(user, "You found something in [source]... it's \a [A][rarity_append]")
 
 	if(unique_loot[loot])
 		var/loot_left = --unique_loot[loot]
@@ -157,8 +187,29 @@
 				mean_loot_weight += loot_table[A]
 			mean_loot_weight /= length(loot_table)
 
-	if(!free)
-		--loot_left_per_atom[source]
-		if(del_atom_on_depletion && !loot_left_per_atom[source])
-			source.visible_message("<span class='warning'>[src] has been looted clean.</span>")
-			qdel(source)
+	if(free)
+		return
+
+	--loot_left_per_atom[source]
+	if(del_atom_on_depletion && !loot_left_per_atom[source])
+		source.visible_message("<span class='warning'>[source] has been looted clean.</span>")
+		qdel(source)
+		return
+
+	if(!loot_restriction)
+		return
+
+	LAZYINITLIST(scavenger_restriction_list)
+	switch(loot_restriction)
+		if(LOOT_RESTRICTION_MIND)
+			scavenger_restriction_list[user.mind]++
+		if(LOOT_RESTRICTION_CKEY)
+			scavenger_restriction_list[user.ckey]++
+		if(LOOT_RESTRICTION_MIND_PILE)
+			LAZYINITLIST(scavenger_restriction_list[source])
+			var/list/L = scavenger_restriction_list[source]
+			L[user.mind]++
+		if(LOOT_RESTRICTION_CKEY_PILE)
+			LAZYINITLIST(scavenger_restriction_list[source])
+			var/list/L = scavenger_restriction_list[source]
+			L[user.ckey]++

code/game/objects/structures/loot_pile.dm

@@ -6,6 +6,7 @@
 	name = "pile of junk"
 	desc = "Lots of junk lying around. They say one man's trash is another man's treasure."
 	icon = 'icons/obj/loot_piles.dmi'
+	icon_state = "randompile"
 	density = FALSE
 	anchored = TRUE
 	var/loot_amount = 5
@@ -14,43 +15,20 @@
 	var/scavenge_time = 12 SECONDS
 	var/allowed_tools = list(TOOL_SHOVEL = 0.6) //list of tool_behaviours with associated speed multipliers (lower is better)
 	var/icon_states_to_use = list("junk_pile1", "junk_pile2", "junk_pile3", "junk_pile4", "junk_pile5")
-	var/list/loot = list(
-		SCAVENGING_FOUND_NOTHING = 50,
-		SCAVENGING_SPAWN_MOUSE = 10,
-		SCAVENGING_SPAWN_MICE = 5,
-		SCAVENGING_SPAWN_TOM = 1,
-		/obj/item/flashlight/flare = 10,
-		/obj/item/flashlight/glowstick = 10,
-		/obj/item/flashlight/glowstick/blue = 10,
-		/obj/item/flashlight/glowstick/orange = 10,
-		/obj/item/flashlight/glowstick/red = 10,
-		/obj/item/flashlight/glowstick/yellow = 10,
-		/obj/item/clothing/mask/gas = 5,
-		/obj/item/clothing/mask/breath = 10,
-		/obj/item/storage/box = 10,
-		/obj/item/clothing/shoes/galoshes = 2,
-		/obj/item/clothing/shoes/sneakers/black = 10,
-		/obj/item/clothing/gloves/color/fyellow = 5,
-		/obj/item/clothing/gloves/color/yellow = 2,
-		/obj/item/clothing/glasses/sunglasses = 3,
-		/obj/item/clothing/glasses/meson = 3,
-		/obj/item/clothing/glasses/welding = 3,
-		/obj/item/clothing/head/hardhat = 10,
-		/obj/item/clothing/head/ushanka = 10,
-		/obj/item/clothing/head/welding = 5,
-		/obj/item/clothing/suit/hazardvest = 10,
-		/obj/item/clothing/under/syndicate/tacticool = 5,
-		/obj/item/clothing/under/pants/camo = 10,
-		/obj/item/stack/spacecash/c10 = 20,
-		/obj/item/stack/spacecash/c20 = 20,
-		/obj/item/stack/spacecash/c50 = 20,
-		/obj/item/radio/headset = 10)
+	var/list/loot
 
  /*
   * Associated values in this list are not weights but numbers of times the kery can be rolled
   * before being removed from ALL piles with same kind. This is why I wanted 'scavenging' to be an element and not a component.
   */
-	var/list/unique_loot = list(/obj/item/clothing/gloves/color/yellow = 2, SCAVENGING_SPAWN_TOM = 1)
+	var/list/unique_loot
+
+ /*
+  * used for restrictions such as "one per mind", "one per ckey". Depending on the setting, these can be either limited to
+  * the current pile or shared throughout all atoms attached to this element.
+  */
+	var/loot_restriction = NO_LOOT_RESTRICTION
+	var/maximum_loot_per_player = 1
 
 /obj/structure/loot_pile/Initialize()
 	. = ..()
@@ -58,9 +36,31 @@
 
 /obj/structure/loot_pile/ComponentInitialize()
 	. = ..()
-	AddElement(/datum/element/scavenging, loot_amount, loot, unique_loot, scavenge_time, can_use_hands, allowed_tools, null, delete_on_depletion)
+	if(loot)
+		AddElement(/datum/element/scavenging, loot_amount, loot, unique_loot, scavenge_time, can_use_hands, allowed_tools, null, delete_on_depletion, loot_restriction, maximum_loot_per_player)
 
-/obj/structure/loot_pile/infinite
-	name = "endless pile of junk."
-	desc = "Lots of awful code lying around. They don't say one coder's trash is another coder's treasure though..."
-	loot_amount = INFINITY
+//uses the maintenance_loot global list, mostly boring stuff and mices.
+/obj/structure/loot_pile/maint
+	name = "trash pile"
+	desc = "A heap of garbage, but maybe there's something interesting inside?"
+	density = TRUE
+	layer = TABLE_LAYER
+	climbable = TRUE
+	pass_flags = LETPASSTHROW
+	loot = list(
+		SCAVENGING_FOUND_NOTHING = 50,
+		SCAVENGING_SPAWN_MOUSE = 10,
+		SCAVENGING_SPAWN_MICE = 5,
+		SCAVENGING_SPAWN_TOM = 1,
+		/obj/item/clothing/gloves/color/yellow = 0.5)
+	unique_loot = list(/obj/item/clothing/gloves/color/yellow = 5, SCAVENGING_SPAWN_TOM = 1)
+
+/obj/structure/loot_pile/maint/ComponentInitialize()
+	var/static/safe_maint_items
+	if(!safe_maint_items)
+		safe_maint_items = list()
+		for(var/A in GLOB.maintenance_loot)
+		if(ispath(A, /obj/item))
+			safe_maint_items[A] = GLOB.maintenance_loot[A]
+	loot += safe_maint_items
+	return ..()