Acetone and Wax
My rub rail (rubber type on the newer Hunters)went completely black and no cleaner seemed to be able to clean the dirt off. Out of desperation, I tried a little acetone. The acetone cleaned the dirt off very well. However, it all the dirt seemed to come back very quickly. I discovered that if I followed the acetone wash with a good quality wax sealer, the rail stayed clean for about a year. Furthermore, I could clean off the stains and dirt with a wet rag. I just finished the process for the second time. The rail looks like new. Remember, Acetone is highly volitile and needs to be used with considerable care.