Mixing metals

This seems to be a bit of science question...hope it's in the right place.

I use brass fittings, always have and never had a problem until recently. I picked up some "stainless steel" washers from Lowes only to find out they were zinc plated steel....washers must have been in the wrong bin and I was in a rush, shame on me.

Now I realized they were zinc coated steel after they started to rust...but now the copper fittings that were in contact with these washers are going south....they've turned black and started to form some of the crusty green oxide where there were in direct contact with the washers.

Should I replace these fittings or will cleaning them (acid bath or salt/vinigar paste) be enough to bring them back.

I've replace the zinc/steel washers with ss washers.

Just clean them.

Copper always comes back. 50/50 water vinegar will do it or a mix of starsan/water if you have it.

I was hoping that was the case!

Thanks

Just had the same issue... My copper came back fine with a Starsan soak, hot water rinse, and rub with a clean rag. My 'SS' washers from the big orange box were even listed as Stainless, not zinc. Had to make a trip to Tacoma Screw, but now everything should be all good.

Some stainless steel will still rust because some has iron in it, while other grades do not. While you obviously do not want stainless steel that rusts it's not necessarily of low quality. I just thought I'd through that out there...