I am cleaning several old machines right now, and have faceplates in all levels of rust. I have been using just elbow grease and metal polish, but have some dark brown areas that appear to have no chrome on them- I also have some that have lots of chrome but little tiny pits everywhere.
What are the recommendations for cleaning when the chrome isn't intact? I have seen ketchup, toothpaste, baking soda... are these ok on a damaged area? what else works?