diff --git a/mods/ITEMS/mcl_core/craftitems.lua b/mods/ITEMS/mcl_core/craftitems.lua
index 2428bb5ea..886535473 100644
--- a/mods/ITEMS/mcl_core/craftitems.lua
+++ b/mods/ITEMS/mcl_core/craftitems.lua
@@ -28,7 +28,6 @@ minetest.register_craftitem("mcl_core:coal_lump", {
 	description = S("Coal"),
 	_doc_items_longdesc = S("“Coal” refers to coal lumps obtained by digging coal ore which can be found underground. Coal is your standard furnace fuel, but it can also be used to make torches, coal blocks and a few other things."),
 	_doc_items_hidden = false,
-	groups = { coal=1 },
 	inventory_image = "default_coal_lump.png",
 	stack_max = 64,
 	groups = { craftitem=1, coal=1 },
@@ -38,7 +37,6 @@ minetest.register_craftitem("mcl_core:charcoal_lump", {
 	description = S("Charcoal"),
 	_doc_items_longdesc = S("Charcoal is an alternative furnace fuel created by cooking wood in a furnace. It has the same burning time as coal and also shares many of its crafting recipes, but it can not be used to create coal blocks."),
 	_doc_items_hidden = false,
-	groups = { coal=1 },
 	inventory_image = "mcl_core_charcoal.png",
 	stack_max = 64,
 	groups = { craftitem=1, coal=1 },
diff --git a/mods/ITEMS/mcl_core/functions.lua b/mods/ITEMS/mcl_core/functions.lua
index 732c386b0..a6c21302e 100644
--- a/mods/ITEMS/mcl_core/functions.lua
+++ b/mods/ITEMS/mcl_core/functions.lua
@@ -24,7 +24,7 @@ minetest.register_abm({
 
 		for w=1, #water do
 			local waternode = minetest.get_node(water[w])
-			local watertype = minetest.registered_nodes[waternode.name].liquidtype
+			--local watertype = minetest.registered_nodes[waternode.name].liquidtype
 			-- Lava on top of water: Water turns into stone
 			if water[w].y < pos.y and water[w].x == pos.x and water[w].z == pos.z then
 				minetest.set_node(water[w], {name="mcl_core:stone"})
@@ -336,13 +336,12 @@ end
 -- oak tree.
 function mcl_core.generate_tree(pos, tree_type, options)
 	pos.y = pos.y-1
-	local nodename = minetest.get_node(pos).name
+	--local nodename = minetest.get_node(pos).name
 
 	pos.y = pos.y+1
 	if not minetest.get_node_light(pos) then
 		return
 	end
-	local node
 
 	local two_by_two = options and options.two_by_two
 	local balloon = options and options.balloon
@@ -390,7 +389,7 @@ end
 function mcl_core.generate_v6_oak_tree(pos)
 	local trunk = "mcl_core:tree"
 	local leaves = "mcl_core:leaves"
-	local node = {name = ""}
+	local node
 	for dy=1,4 do
 		pos.y = pos.y+dy
 		if minetest.get_node(pos).name ~= "air" then
@@ -409,10 +408,10 @@ function mcl_core.generate_v6_oak_tree(pos)
 
 	node = {name = leaves}
 	pos.y = pos.y+3
-	local rarity = 0
+	--[[local rarity = 0
 	if math.random(0, 10) == 3 then
 		rarity = 1
-	end
+	end]]
 	for dx=-2,2 do
 		for dz=-2,2 do
 			for dy=0,3 do
@@ -787,7 +786,6 @@ minetest.register_abm({
 		if pos == nil then
 			return
 		end
-		local can_change = false
 		local above = {x=pos.x, y=pos.y+1, z=pos.z}
 		local abovenode = minetest.get_node(above)
 		if minetest.get_item_group(abovenode.name, "liquid") ~= 0 or minetest.get_item_group(abovenode.name, "opaque") == 1 then
@@ -1021,7 +1019,7 @@ local sapling_grow_action = function(tree_id, soil_needed, one_by_one, two_by_tw
 			if one_by_one and check_tree_growth(pos, tree_id) then
 				-- Single sapling
 				minetest.set_node(pos, {name="air"})
-				local r = math.random(1, 12)
+				--local r = math.random(1, 12)
 				mcl_core.generate_tree(pos, tree_id)
 				return
 			end
@@ -1418,7 +1416,7 @@ minetest.register_abm({
 			for s=1, #surround do
 				local spos = vector.add(p0, surround[s])
 				local maybe_vine = minetest.get_node(spos)
-				local surround_inverse = vector.multiply(surround[s], -1)
+				--local surround_inverse = vector.multiply(surround[s], -1)
 				if maybe_vine.name == "mcl_core:vine" and (not mcl_core.check_vines_supported(spos, maybe_vine)) then
 					minetest.remove_node(spos)
 					vinedecay_particles(spos, maybe_vine)