does anyone have any tips for cleaning samsonite train cases? the tips i found online mostly said a clean rag and warm soapy water, but that isn't working on this one. didn't find anything on samsonite's website either. there are black scuff marks and something sticky that's not coming off on the case! i don't want to damage the finish or the color by using goo gone or a harsh cleaner. maybe vinegar? it also has a musky smell inside of it. any tips or tricks ? thanks!!!