Iron Nugget Recycling lets you smelt most iron-requiring items into Iron Nuggets. This can be especially useful when exploring a structure containing blocks such as Iron Bars or Rails. You can also use it to get some iron back when you craft too many Iron Doors etc.
This is a mod, data pack version available here.
For Gold Nuggets check out Gold Nugget Recycling!
List of items that can now be smelted into Iron Nuggets:
