Click the anvil to add an item. Type the item that you want to filter out. For example "Iron Helmet" "Iron Chestplate" "Iron Leggings "Iron Boots" Those work fine for me. Then, after you listed the items you want to filter out, make sure to click the block on the top right to enable it. Lastly, you must make sure the book says "Blacklist" not "Whitelisted" in order for it to enable completely. After that you should be 100% fine! Requesting lock, answered question!how does it work like i try to add item in the list but i cant it tell me invalid