Any suggestions for a good stain remover for marine vinyl? I scrubbed the 12 year old interior with Zep purple de-greaser and a brush and all the dirt, grime and mildew came off. It even took off the oil and dirt but there are still some black stains left. Is there anything I can use to treat just those spots and what is good to condition the rest of the stuff. Since we are doing the motor and drive this year, a new interior will have to wait a while.