guide to annealing allyI've only used the engine oil method myself, but soap works too according to google... It's mainly about making sure you don't over-heat it, with the oil. No idea what the soap is meant to do (not convinced by what I read on google)
https://makeitfrommetal.com/how-to-...minum requires very,to soak through the metal.
and the soap goes brown at the right temp (quick answer)!