Have you ever at any point in your life wanna revert your ores back into the block you mined it from? Well me neither, but now you can!
Just put your ore in the middle of your crafting table, and fill the other slots with deepslate or stone, and boom, you got it.
Also works for nether ores, but use gold nuggets instead of ingots, and netherrack instead of stone/deepslate.