diff --git a/technic/tools/cans.lua b/technic/tools/cans.lua
index f46a401..f12ec93 100644
--- a/technic/tools/cans.lua
+++ b/technic/tools/cans.lua
@@ -12,6 +12,14 @@ local function set_can_wear(itemstack, level, max_level)
 	itemstack:set_wear(temp)
 end
 
+local function get_can_level(itemstack)
+	if itemstack:get_metadata() == "" then
+		return 0
+	else
+		return tonumber(itemstack:get_metadata())
+	end
+end
+
 function technic.register_can(d)
 	local data = {}
 	for k, v in pairs(d) do data[k] = v end
@@ -22,46 +30,44 @@ function technic.register_can(d)
 		wear_represents = "content_level",
 		liquids_pointable = true,
 		on_use = function(itemstack, user, pointed_thing)
-			if pointed_thing.type ~= "node" then
+			if pointed_thing.type ~= "node" then return end
+			local node = minetest.get_node(pointed_thing.under)
+			if node.name ~= data.liquid_source_name then return end
+			local charge = get_can_level(itemstack)
+			if charge == data.can_capacity then return end
+			if minetest.is_protected(pointed_thing.under, user:get_player_name()) then
+				minetest.log("action", user:get_player_name().." tried to take "..node.name.." at protected position "..minetest.pos_to_string(pointed_thing.under).." with a "..data.can_name)
 				return
 			end
-			node = minetest.get_node(pointed_thing.under)
-
-			local charge = nil
-			if itemstack:get_metadata() == "" then
-				charge = 0
-			else
-				charge = tonumber(itemstack:get_metadata())
+			minetest.remove_node(pointed_thing.under)
+			charge = charge + 1
+			itemstack:set_metadata(tostring(charge))
+			set_can_wear(itemstack, charge, data.can_capacity)
+			return itemstack
+		end,
+		on_place = function(itemstack, user, pointed_thing)
+			if pointed_thing.type ~= "node" then return end
+			local pos = pointed_thing.under
+			local def = minetest.registered_nodes[minetest.get_node(pos).name] or {}
+			if def.on_rightclick and user and not user:get_player_control().sneak then
+				return def.on_rightclick(pos, minetest.get_node(pos), user, itemstack, pointed_thing)
 			end
-			if node.name == data.liquid_source_name then
-				if charge < data.can_capacity then
-					minetest.remove_node(pointed_thing.under)
-					charge = charge + 1
-					itemstack:set_metadata(tostring(charge))
-					set_can_wear(itemstack, charge, data.can_capacity)
-				end
-				return itemstack
+			if not def.buildable_to then
+				pos = pointed_thing.above
+				def = minetest.registered_nodes[minetest.get_node(pos).name] or {}
+				if not def.buildable_to then return end
 			end
-			if charge == 0 then
+			local charge = get_can_level(itemstack)
+			if charge == 0 then return end
+			if minetest.is_protected(pos, user:get_player_name()) then
+				minetest.log("action", user:get_player_name().." tried to place "..data.liquid_source_name.." at protected position "..minetest.pos_to_string(pos).." with a "..data.can_name)
 				return
 			end
-
-			if node.name == data.liquid_flowing_name then
-				minetest.set_node(pointed_thing.under, {name=data.liquid_source_name})
-				charge = charge - 1
-				itemstack:set_metadata(tostring(charge))
-				set_can_wear(itemstack, charge, data.can_capacity)
-				return itemstack
-			end
-
-			node = minetest.get_node(pointed_thing.above)
-			if node.name == "air" then
-				minetest.set_node(pointed_thing.above, {name=data.liquid_source_name})
-				charge = charge - 1
-				itemstack:set_metadata(tostring(charge))
-				set_can_wear(itemstack, charge, data.can_capacity)
-				return itemstack
-			end		
+			minetest.set_node(pos, {name=data.liquid_source_name})
+			charge = charge - 1
+			itemstack:set_metadata(tostring(charge))
+			set_can_wear(itemstack, charge, data.can_capacity)
+			return itemstack
 		end,
 		on_refill = function(stack)
 			stack:set_metadata(tostring(data.can_capacity))