Before I replaced my flares, I did use the Krylon fusion paint to blacken them up. It worked great and really held up. I had them for a year and a half before I replaced them. No chips or cracks in the paint, and they hadn't faded. I just went to a wider flare. To do it right, remove them from the Jeep, wash them and rub them with acetone. Then after they're dry, hit em with the paint.That's not mine, Its someone else that posted up on here a couple weeks ago. I am sure that the paint would definitely hold up better than any kind of treatment. It may be something you have to do yearly or so but it would really be worth it to keep those flares looking good, makes a jeep look so much better!! I don't think there is a lot of prep work involved either. I would just wash them up really well and paint them. They say the fusion bonds with plastic like glue!!