Dirt overlay fixes

code/game/turfs/simulated.dm

@@ -27,18 +27,15 @@
 
 	if (istype(A,/mob/living/carbon))
 		var/mob/living/carbon/M = A
-		var/obj/effect/decal/cleanable/dirt/dirttile = dirtoverlay
 		if(M.lying)	return
 		dirt++
+		var/obj/effect/decal/cleanable/dirt/dirtoverlay = locate(/obj/effect/decal/cleanable/dirt, src)
 		if (dirt >= 30)
-			if (!locate(/obj/effect/decal/cleanable/dirt, src))
+			if (!dirtoverlay)
 				dirtoverlay = new/obj/effect/decal/cleanable/dirt(src)
-				dirttile = dirtoverlay
-				dirttile.alpha = 15
-		if (dirt > 30 && dirtoverlay && dirttile.alpha <= 255)
-			dirttile.alpha += 20
-		if (dirt == 0)
-			dirtoverlay = null
+				dirtoverlay.alpha = 15
+			else if (dirt > 30)
+				dirtoverlay.alpha = min(dirtoverlay.alpha+20, 255)
 		if(istype(M, /mob/living/carbon/human))
 			var/mob/living/carbon/human/H = M
 			if(istype(H.shoes, /obj/item/clothing/shoes/clown_shoes))

code/modules/mob/living/silicon/robot/robot.dm

@@ -1168,6 +1168,9 @@
 			var/turf/tile = loc
 			if(isturf(tile))
 				tile.clean_blood()
+				if (istype(tile, /turf/simulated))
+					var/turf/simulated/S = tile
+					S.dirt = 0
 				for(var/A in tile)
 					if(istype(A, /obj/effect))
 						if(istype(A, /obj/effect/rune) || istype(A, /obj/effect/decal/cleanable) || istype(A, /obj/effect/overlay))

code/modules/reagents/Chemistry-Reagents.dm

@@ -1299,7 +1299,9 @@ datum
 
 					for(var/mob/living/carbon/slime/M in T)
 						M.adjustToxLoss(rand(5,10))
-
+			reaction_turf(var/turf/simulated/S, var/volume)
+				if(volume >= 1)
+					S.dirt = 0
 			reaction_mob(var/mob/M, var/method=TOUCH, var/volume)
 				if(iscarbon(M))
 					var/mob/living/carbon/C = M