Discoloured Stainless Steel

[Magnus]

A friend of mine owns a metal lathe and was working some stainless steel bar, and due to the heat it turned an interesting rosey copper colour. I know brass and other metals do the same...will a 50/50 vinnegar water solution get rid of the discolouration?

[LUCIUS ALFENUS AVITIANUS]

Vinegar is a acid (acetic). We can use it to clean the surfaces of the heat coloured metals. Jewellers use more strong acids in a low concentration (sulfuric, etc...) but probably it's more dangerous.

I use vinegar without disolution. When the metal is clean, clean the piece with bicarbonate, to neautralize the acid action, and then dry the piece.