Fixes #10548

code/game/objects/items/weapons/clown_items.dm

@@ -32,7 +32,7 @@
 	else if(istype(target,/turf))
 		user << "<span class='notice'>You scrub \the [target.name] clean.</span>"
 		var/turf/T = target
-		T.clean()
+		T.clean(src)
 	else
 		user << "<span class='notice'>You clean \the [target.name].</span>"
 		target.clean_blood()

code/game/objects/items/weapons/mop.dm

@@ -16,6 +16,7 @@
 /obj/item/weapon/mop/New()
 	create_reagents(5)
 
+//expects an atom containing the reagents used to clean the turf
 /turf/proc/clean(atom/source)
 	if(source.reagents.has_reagent("water", 1))
 		clean_blood()