Remember "one" of my main rules on cleaning and care of anything is prevention. Stains become tremendously more difficult to remove when vinyl or leather is allowed to become dry. Dryness eventually leads to cracking, which leads to expensive replacement.
You must be apply a leather/vinyl conditioner to any leather or vinyl seat, chair or couch at least twice a year and boat seats three to four times a year. This is especially important for boat seats that tend to become moldy and dry more quickly due to exposure to the elements.
Just remember after you remove a stain if you are using a general cleaner or something I recommend below, you must condition the seats afterwards or they will dry which will only lead to more difficulty later in cleaning them.
Some common boat stains involve: tree sap or leaves from trees; swimsuits or towels that have left a dye on the seats; spilled drinks, grease or oil and mold or mildew.
1) For tree sap or leaves; grease and oil including fried food or Fido's slobbering on the seats and heavy dirt. Usually most of these stains can be removed with foaming tub and tile cleaner either that made by Lysol or Dow. No I do not like this stuff in the shower or bathroom. It's completely useless there and an expensive way to clean. But for some reason those little foaming bubbles seem to remove these kinds of dirt and grime.
If you are dealing with oil or grease from perhaps your engine then try a foaming shaving cream. The gel won't work but sometimes the 3 kinds of alcohol in the foaming shaving cream will zap that stuff off without damaging the vinyl.
2) Dye from swimsuits, towels, red dye from food or drinks: I don't know that these stains will come out. Try pouring some baking soda on the stain then spraying that with hydrogen peroxide a fresh bottle please. It will bubble and fizzle which helps sometimes to remove a stain. Do not leave this on longer than 10 minutes and rinse thoroughly. If that does not remove the stain leave it alone as anything else strong enough to remove the stain will "burn" the vinyl.
3) Mold and mildew: My CleanEz will kill mold and mildew to prevent it from worsening. However, once mold or mildew has been allowed to get a strong hold in either vinyl or leather, the stain itself usually will not come out. Try the method in #2 but I doubt if you can remove the stain.
4) Dirt and grime: Try a foaming tub and tile cleaner then condition with Leather/Vinyl Care is the best you can buy for cleaning and conditioning vinyl or leather.
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