diff --git a/changelog.txt b/changelog.txt
index 3c21789bbc..0cc9c17f5d 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -27,6 +27,7 @@ Template for new versions:
 # Future
 
 ## New Tools
+- `undump-buildings`: (reinstated) remove dump designation from in-use building materials
 
 ## New Features
 
diff --git a/docs/undump-buildings.rst b/docs/undump-buildings.rst
index 8848442734..34fb4ef05f 100644
--- a/docs/undump-buildings.rst
+++ b/docs/undump-buildings.rst
@@ -3,7 +3,7 @@ undump-buildings
 
 .. dfhack-tool::
     :summary: Undesignate building base materials for dumping.
-    :tags: unavailable
+    :tags: fort productivity buildings
 
 If you designate a bunch of tiles in dump mode, all the items on those tiles
 will be marked for dumping. Unfortunately, if there are buildings on any of
diff --git a/undump-buildings.lua b/undump-buildings.lua
index d8bf60c5aa..50f4e4f96a 100644
--- a/undump-buildings.lua
+++ b/undump-buildings.lua
@@ -1,35 +1,20 @@
--- Undesignates building base materials for dumping.
---[====[
-
-undump-buildings
-================
-Undesignates building base materials for dumping.
-
-]====]
-
 function undump_buildings()
-    local buildings = df.global.world.buildings.all
     local undumped = 0
-    for i = 0, #buildings - 1 do
-        local building = buildings[i]
+    for _, building in ipairs(df.global.world.buildings.all) do
         -- Zones and stockpiles don't have the contained_items field.
-        if df.building_actual:is_instance(building) then
-            local items = building.contained_items --hint:df.building_actual
-            for j = 0, #items - 1 do
-                local contained = items[j]
-                if contained.use_mode == 2 and contained.item.flags.dump then
-                    -- print(building, contained.item)
-                    undumped = undumped + 1
-                    contained.item.flags.dump = false
-                end
+        if not df.building_actual:is_instance(building) then goto continue end
+        for _, contained in ipairs(building.contained_items) do
+            if contained.use_mode == 2 and contained.item.flags.dump then
+                undumped = undumped + 1
+                contained.item.flags.dump = false
             end
         end
+        ::continue::
     end
 
     if undumped > 0 then
-        local s = "s"
-        if undumped == 1 then s = "" end
-        print("Undumped "..undumped.." item"..s..".")
+        local s = undumped == 1 and '' or 's'
+        print(('Undumped %s in-use building item%s'):format(undumped, s))
     end
 end