Some spawn removals and other assorted code cleanup

code/modules/reagents/chemistry/recipes/pyrotechnics.dm

@@ -164,8 +164,7 @@
 /datum/chemical_reaction/blackpowder_explosion/on_reaction(datum/reagents/holder, created_volume)
 	var/location = get_turf(holder.my_atom)
 	do_sparks(2, 1, location)
-	spawn(rand(5, 15))
-		blackpowder_detonate(holder, created_volume)
+	addtimer(CALLBACK(null, .proc/blackpowder_detonate, holder, created_volume), rand(5, 15))
 
 /proc/blackpowder_detonate(datum/reagents/holder, created_volume)
 	var/turf/T = get_turf(holder.my_atom)
@@ -176,8 +175,7 @@
 	explosion(T, ex_severe, ex_heavy,ex_light, ex_flash, 1)
 	// If this black powder is in a decal, remove the decal, because it just exploded
 	if(istype(holder.my_atom, /obj/effect/decal/cleanable/dirt/blackpowder))
-		spawn(0)
-			qdel(holder.my_atom)
+		qdel(holder.my_atom)
 
 /datum/chemical_reaction/flash_powder
 	name = "Flash powder"

code/modules/reagents/reagent_containers/pill.dm

@@ -23,13 +23,12 @@
 
 /obj/item/reagent_containers/food/pill/attack(mob/living/carbon/M, mob/user, def_zone)
 	if(!istype(M))
-		return 0
+		return FALSE
 	bitesize = reagents.total_volume
 	if(M.eat(src, user))
-		spawn(0)
-			qdel(src)
-		return 1
-	return 0
+		qdel(src)
+		return TRUE
+	return FALSE
 
 /obj/item/reagent_containers/food/pill/afterattack(obj/target, mob/user, proximity)
 	if(!proximity)

code/modules/reagents/reagent_containers/spray.dm

@@ -44,7 +44,7 @@
 		return
 
 	var/contents_log = reagents.reagent_list.Join(", ")
-	spray(A)
+	INVOKE_ASYNC(src, .proc/spray, A)
 
 	playsound(loc, 'sound/effects/spray2.ogg', 50, 1, -6)
 	user.changeNext_move(CLICK_CD_RANGE*2)
@@ -62,19 +62,19 @@
 	return
 
 
-/obj/item/reagent_containers/spray/proc/spray(var/atom/A)
+/obj/item/reagent_containers/spray/proc/spray(atom/A)
 	var/obj/effect/decal/chempuff/D = new /obj/effect/decal/chempuff(get_turf(src))
 	D.create_reagents(amount_per_transfer_from_this)
 	reagents.trans_to(D, amount_per_transfer_from_this, 1/spray_currentrange)
 	D.icon += mix_color_from_reagents(D.reagents.reagent_list)
-	spawn(0)
-		for(var/i=0, i<spray_currentrange, i++)
-			step_towards(D,A)
-			D.reagents.reaction(get_turf(D))
-			for(var/atom/T in get_turf(D))
-				D.reagents.reaction(T)
-			sleep(3)
-		qdel(D)
+
+	for(var/i in 1 to spray_currentrange)
+		step_towards(D, A)
+		D.reagents.reaction(get_turf(D))
+		for(var/atom/T in get_turf(D))
+			D.reagents.reaction(T)
+		sleep(3)
+	qdel(D)
 
 
 /obj/item/reagent_containers/spray/attack_self(var/mob/user)