just need items to actually have their overlays, ree

code/game/objects/effects/decals/cleanable.dm

@@ -8,6 +8,7 @@
 
 /obj/effect/decal/cleanable/Initialize(mapload, list/datum/disease/diseases)
 	. = ..()
+	LAZYINITLIST(blood_DNA) //Kinda needed
 	if (random_icon_states && (icon_state == initial(icon_state)) && length(random_icon_states) > 0)
 		icon_state = pick(random_icon_states)
 	create_reagents(300)
@@ -27,7 +28,7 @@
 
 /obj/effect/decal/cleanable/proc/replace_decal(obj/effect/decal/cleanable/C) // Returns true if we should give up in favor of the pre-existing decal
 	if(mergeable_decal)
-		return TRUE
+		qdel(C)
 
 /obj/effect/decal/cleanable/attackby(obj/item/W, mob/user, params)
 	if(istype(W, /obj/item/reagent_containers/glass) || istype(W, /obj/item/reagent_containers/food/drinks))
@@ -81,7 +82,7 @@
 				add_blood = bloodiness
 			bloodiness -= add_blood
 			S.bloody_shoes[blood_state] = min(MAX_SHOE_BLOODINESS,S.bloody_shoes[blood_state]+add_blood)
-			if(blood_DNA && blood_DNA.len)
+			if(length(blood_DNA))
 				S.add_blood_DNA(blood_DNA)
 			S.blood_state = blood_state
 			update_icon()