Re: 65 Starcraft - were the cleats aluminum or chrome?
My guess is Zamac, a zinc alloy. Then they are chromed. It's not worth it to surface prepare (remove the old chrome) and then re-chrome plate. If they were 300 series stainless they wouldn't pit up.
New cleats are cheap, even the solid stainless steel ones. I need to replace all the chrome pieces on my boat, clamshells, cleats etc, due to pitting.