Use a grindstone to remove most enchantments from an item
Place the enchanted item in one input slot of the grindstone
Take the resulting item from the output slot
Note that curses cannot be removed with a grindstone
Use a crafting table with two of the same damaged items to combine them and remove enchantments from both, if applicable
Use an anvil with a book or another item only if you want to keep or transfer enchantments, not disenchant them
Use commands in Creative mode or with cheats enabled to clear enchantments from an item
Use the `/enchant` command only to add enchantments, not remove them