Add "clean" mod.

README.md

@@ -5,6 +5,7 @@ The game includes the mods from the default [minetest_game](https://github.com/m
 
 The following mods are also included:
 * admin/
+    * [clean][] (WTFPL)
     * [invisible][] ([LGPL / CC BY-SA](mods/admin/invisible/readme.txt))
 * [adv_spawning][] ([???](mods/adv_spawning/README.txt))
 * [animalmaterials (modpack)][animalmaterials] (CC-BY-SA / CC0)
@@ -136,6 +137,7 @@ The following mods are also included:
 [character_creator]: https://forum.minetest.net/viewtopic.php?f=9&t=13138
 [chatlog]: https://forum.minetest.net/viewtopic.php?id=6220
 [christmas]: https://forum.minetest.net/viewtopic.php?t=3950
+[clean]: https://forum.minetest.net/viewtopic.php?t=2777
 [cme]: https://forum.minetest.net/viewtopic.php?t=8638
 [compass]: https://forum.minetest.net/viewtopic.php?t=3785
 [compassgps]: https://forum.minetest.net/viewtopic.php?t=9373

mods/admin/clean/init.lua

@@ -0,0 +1,28 @@
+-- LICENSE: WTFPL
+-- Copyright: PilzAdam
+
+local old_nodes = {"mod:a", "mod:b"}
+local old_entities = {}
+
+for _,node_name in ipairs(old_nodes) do
+    minetest.register_node(":"..node_name, {
+        groups = {old=1},
+    })
+end
+
+minetest.register_abm({
+    nodenames = {"group:old"},
+    interval = 1,
+    chance = 1,
+    action = function(pos, node)
+        minetest.env:remove_node(pos)
+    end,
+})
+
+for _,entity_name in ipairs(old_entities) do
+    minetest.register_entity(":"..entity_name, {
+        on_activate = function(self, staticdata)
+            self.object:remove()
+        end,
+    })
+end