Denny:
The easiest way to get pitting in stainless trim is to have it in a shop where there is grinding of steel, and the steel particles get on the stainless. If it gets wet, or if the steel particles are hot enough to embed in the stainless (its melting point is less than steel), then it will form pits, as you describe. Take a guess how we know this. And it gets worse as it sits longer and longer in humid conditions.
Non-magnetic stainless seems to be more prone to this problem than the magnetic 400 series stainless, at least in our experience.
Mar-Ktech
