Buff and Polish using 3m perfect it two stage creams. I forget the names of each but they're not too hard to find if you search around for it. Fantastic results on gel coat, just be careful to not stay on one spot too long or apply too much pressure or you'll burn the gel coat. For the rubber/plastic, try forever black (for black color) it's a great fade resistant plastic conditioner. You can also do the heat gun trick, but that has short term results imo. Maybe a couple months