We mistakenly stored a bottle of water in the kitchen sink while underway resulting in some noticeable scratching. Once scratched the sink developed some serious coffee stains and we figured that we'd have to replace the sink. Robert suggested we try his polish before going through the hassle of replacing it. Sure enough it worked great!
The polish cleaned the sink well and also smoothed some of the roughness so it didn't stain as badly in the future. We're believers too!