Q: How can I remove exhaust stains on the transom and stern area? They don’t come off with boat soap or spray cleaners very well.
A: Exhaust stains can turn a white transom gray and make an otherwise clean boat look dirty. Exhaust stains won’t harm your gel coat, but for cosmetic purposes, it’s something you probably want to keep on top of. However, as many of you know, they don’t always come off in the wash. Some spray cleaners are strong enough to remove exhaust stains, however if they’re strong enough for that job, then they’re probably also strong enough to eventually strip that area of wax, only making it harder to clean the exhaust stains off over time. The only way to remove them at that point is to buff and wax that area. Yes, it’s a vicious circle that you’re on, so how about skipping a step and going straight to the wax.
The best way to remove exhaust stains from gel coat is to wax them off. This is something that can easily be done by hand with cleaner wax, such as Meguiars Cleaner Wax. Use any kind of rag to apply the wax with (terry cloth or an old t-shirt) and wipe or rub it in until the exhaust stains are gone. Then use a microfiber rag to wipe the hazy wax dust off. You’ll be left with a nice clean, white surface again and it should be a little easier to wipe exhaust stains off the next time since they’ll be sitting on top of a freshly waxed surface.