You basically just sand the hazy part out. All that's in those kits are sand paper or equivalent. The only problem is the part that's yellowing is the plastics protection. When you sand it off it's going to yellow again, but pretty fast. You have to wax it weekly and even then it might still slowly yellow again. The best thing to do is sand it down, polish it, then clear coat it to protect it from yellowing again. I'd have them professionally painted at least (since it's a G we're talking about). If you want me to polish them out nicely I can do it for a good price.
:usa: