Smelting trick gives unlimited experience/XP

When you smelt iron into iron ingots, if you have say 32 ingots in your inventory and there are >32 ingots (Total > 64) in the furnace, tap the ingots in the furnace and then tap on to the ingots in your inventory.  You will hear the XP sound, but the ingots won't transfer (separate issue.)  You can keep repeating tapping on the furnace ingots then the inventory ingots and the XP sound will keep happening and your XP bar will keep increasing.  I got from Level 23 to >50 easily this way.

Survival World, Build 947245 Build Date: 2018-05-25