diff --git a/builtin/game/register.lua b/builtin/game/register.lua
index c0c579a25..f286113ec 100644
--- a/builtin/game/register.lua
+++ b/builtin/game/register.lua
@@ -368,13 +368,6 @@ end
 -- Callback registration
 --
 
-local register_biome_raw = core.register_biome
-core.registered_biomes = {}
-function core.register_biome(biome)
-	core.registered_biomes[biome.name] = biome
-	register_biome_raw(biome)
-end
-
 local function make_registration()
 	local t = {}
 	local registerfunc = function(func) table.insert(t, func) end
@@ -387,20 +380,34 @@ local function make_registration_reverse()
 	return t, registerfunc
 end
 
-local function make_registration_wrap(name)
+local function make_registration_wrap(reg_fn_name, clear_fn_name)
 	local list = {}
-	local full_name = "register_"..name
-	local orig_func = core[full_name]
-	core[full_name] = function(def)
-		table.insert(list, def)
-		orig_func(def)
+
+	local orig_reg_fn = core[reg_fn_name]
+	core[reg_fn_name] = function(def)
+		local retval = orig_reg_fn(def)
+		if retval ~= nil then
+			if def.name ~= nil then
+				list[def.name] = def
+			else
+				list[retval] = def
+			end
+		end
+		return retval
 	end
+
+	local orig_clear_fn = core[clear_fn_name]
+	core[clear_fn_name] = function()
+		list = {}
+		return orig_clear_fn()
+	end
+
 	return list
 end
 
-
-core.registered_ores = make_registration_wrap("ore")
-core.registered_decorations = make_registration_wrap("decoration")
+core.registered_biomes      = make_registration_wrap("register_biome",      "clear_registered_biomes")
+core.registered_ores        = make_registration_wrap("register_ore",        "clear_registered_ores")
+core.registered_decorations = make_registration_wrap("register_decoration", "clear_registered_decorations")
 
 core.registered_on_chat_messages, core.register_on_chat_message = make_registration()
 core.registered_globalsteps, core.register_globalstep = make_registration()
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index e2d93a059..6d6625348 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -417,10 +417,20 @@ the global `minetest.registered_*` tables.
     * added to `minetest.registered_items[name]`
 
 * `minetest.register_ore(ore definition)`
-    * added to `minetest.registered_ores`
+    * returns an integer uniquely identifying the registered ore
+    * added to `minetest.registered_ores` with the key of `ore.name`
+    * if `ore.name` is nil, the key is the returned ID
 
 * `minetest.register_decoration(decoration definition)`
-    * added to `minetest.registered_decorations`
+    * returns an integer uniquely identifying the registered decoration
+    * added to `minetest.registered_decorations` with the key of `decoration.name`
+    * if `decoration.name` is nil, the key is the returned ID
+
+* `minetest.clear_registered_ores()`
+   * clears all ores currently registered
+
+* `minetest.clear_registered_decorations()`
+   * clears all decorations currently registered
 
 Note that in some cases you will stumble upon things that are not contained
 in these tables (e.g. when a mod has been removed). Always check for
@@ -1679,6 +1689,9 @@ Call these functions only at load time!
     * Note: Item must already be defined, (opt)depend on the mod defining it.
     * Example: `minetest.override_item("default:mese", {light_source=LIGHT_MAX})`
 
+* `minetest.clear_registered_ores()`
+* `minetest.clear_registered_decorations()`
+
 ### Global callback registration functions
 Call these functions only at load time!