Vinegar is 95% water and 5% acetic acid. Acetic acid, although considered a weak acid, will eat iron & steel. It will also do a pretty good job on copper. It will not bother good quality stainless steels. As for gaskets, it will eventually do a number on nitriles & SBR rubbers. EPDM & PTFE gaskets stand up the best.
I would strongly advise against using any acid and if you do, make sure you get it all out.
Tom B.
(LongLine)