I found that I had to get the wax off before the other products would keep it from happening again. I used a stiff toothbrush to get as much off as possible. I found the Ice to work well to not stain again.

 

Wet the fender with water and spray a little Bleech-White tire cleaner on it and scrub lightly with a tooth brush. Rinse it off thoroughly, let it dry, then put Mop-n-Glow on the whole plastic fender with a sponge. The Mop-n-Glow protects the plastic from UV and keeps it from drying out and turning chalky white like the Armorall products do. BTW, the Mop-n-Glow works well on tires, too, and it keeps the white letters from turning brown.

Mark