Through Hull

[ALLCAPS]

What’s the best way to get the green corrosion off my SS through hull fittings???

 

[seasick]

What’s the best way to get the green corrosion off my SS through hull fittings???

Are you sure they are stainless and not chrome plated bronze?
They may be bronze if original. If so, the chrome may have corroded away exposing the bronze. Unfortunately if the chrome is gone , it can't be restored. If you can lightly scrub or sand the bronze and it gets shiny, it is still OK. If you see bronze that looks a bit yellow in color, the metal is suffering degradation.

 

[DennisG01]

What’s the best way to get the green corrosion off my SS through hull fittings???

Sounds more like you have chromed bronze. Chrome breaks down pretty easily in marine environments. The bronze, however, is extremely durable (better than SS, too!). The green patina you see is not a problem from a functional standpoint - a small amount is totally fine - it's actually the bronze's way of self protecting itself. You could try some metal polish (Flitz, for ex) - but the pitting you see is not going to go away - the chrome is already damaged. If you want to just make them look pretty, and these are above the waterline, you can switch them out to SS ones.