diff --git a/code/game/objects/items.dm b/code/game/objects/items.dm
index 847cad755e..b529211208 100644
--- a/code/game/objects/items.dm
+++ b/code/game/objects/items.dm
@@ -3,7 +3,7 @@
 	icon = 'icons/obj/items.dmi'
 	w_class = ITEMSIZE_NORMAL
 
-	matter = list(DEFAULT_WALL_MATERIAL = 1)
+	matter = list(MAT_STEEL = 1)
 
 	var/image/blood_overlay = null //this saves our blood splatter overlay, which will be processed not to go over the edges of the sprite
 	var/randpixel = 6
diff --git a/code/game/objects/items/apc_frame.dm b/code/game/objects/items/apc_frame.dm
index 1df49c094b..17dc386c42 100644
--- a/code/game/objects/items/apc_frame.dm
+++ b/code/game/objects/items/apc_frame.dm
@@ -6,7 +6,7 @@
 	icon = 'icons/obj/apc_repair.dmi'
 	icon_state = "apc_frame"
 	refund_amt = 2
-	matter = list(DEFAULT_WALL_MATERIAL = 100,"glass" = 30)
+	matter = list(MAT_STEEL = 100, MAT_GLASS = 30)
 
 /obj/item/frame/apc/try_build(turf/on_wall, mob/user as mob)
 	if (get_dist(on_wall, user)>1)
diff --git a/code/game/objects/items/bells.dm b/code/game/objects/items/bells.dm
index 38bf8a7943..e9219957e4 100644
--- a/code/game/objects/items/bells.dm
+++ b/code/game/objects/items/bells.dm
@@ -6,7 +6,7 @@
 	force = 2
 	throwforce = 2
 	w_class = 2.0
-	matter = list(DEFAULT_WALL_MATERIAL = 50)
+	matter = list(MAT_STEEL = 50)
 	var/broken
 	attack_verb = list("annoyed")
 	var/static/radial_examine = image(icon = 'icons/mob/radial.dmi', icon_state = "radial_examine")
diff --git a/code/game/objects/items/trash.dm b/code/game/objects/items/trash.dm
index 1bf28dc3b2..67d899f517 100644
--- a/code/game/objects/items/trash.dm
+++ b/code/game/objects/items/trash.dm
@@ -8,7 +8,7 @@
 	desc = "This is rubbish."
 	drop_sound = 'sound/items/drop/wrapper.ogg'
 	pickup_sound = 'sound/items/pickup/wrapper.ogg'
-	matter = list(DEFAULT_WALL_MATERIAL = 30)
+	matter = list(MAT_STEEL = 30)
 	var/age = 0
 
 /obj/item/trash/New(var/newloc, var/_age)
diff --git a/code/game/objects/items/weapons/AI_modules.dm b/code/game/objects/items/weapons/AI_modules.dm
index 306573f40d..b6e25262eb 100644
--- a/code/game/objects/items/weapons/AI_modules.dm
+++ b/code/game/objects/items/weapons/AI_modules.dm
@@ -18,7 +18,7 @@ AI MODULES
 	throw_range = 15
 	origin_tech = list(TECH_DATA = 3)
 	preserve_item = 1
-	matter = list(DEFAULT_WALL_MATERIAL = 30,"glass" = 10)
+	matter = list(MAT_STEEL = 30, MAT_GLASS = 10)
 	var/datum/ai_laws/laws = null
 
 /obj/item/weapon/aiModule/proc/install(var/atom/movable/AM, var/mob/living/user)
diff --git a/code/game/objects/items/weapons/circuitboards/circuitboard.dm b/code/game/objects/items/weapons/circuitboards/circuitboard.dm
index 437f3038b5..9225046071 100644
--- a/code/game/objects/items/weapons/circuitboards/circuitboard.dm
+++ b/code/game/objects/items/weapons/circuitboards/circuitboard.dm
@@ -16,7 +16,7 @@
 	throwforce = 5.0
 	throw_speed = 3
 	throw_range = 15
-	matter = list(DEFAULT_WALL_MATERIAL = 30,"glass" = 10)
+	matter = list(MAT_STEEL = 30, MAT_GLASS = 10)
 	var/build_path = null
 	var/board_type = new /datum/frame/frame_types/computer
 	var/list/req_components = null