What cleaner?

You can't remove fade on any surface and bring it back to the original (before the stickers were placed there.) The outline pattern of the brighter color under the sticker area will always be noticeable. The only solutions are to repaint the entire surface so everything matches, or cover with a bigger sticker.

Sounds like your trailer skin is a "laminate"...

“laminate” – ... taking a resin plastic, reinforcing it (often with fiberglass) and then treating it with a gel-coat. The end result is then laminated onto a backer board and ultimately onto a superstructure of the RV-manufacturer’s choice.

https://rv-pro.com/features/great-debate-laminates-vs-stick-and-tin

try something like 409 to remove all the oxidation, etc. then polish with either a very fine polish or polish/wax. You'll not get the fading to go away but it might look a little better. It happens very fast, I had a sticker on for about a year, removed it 5 years ago and you can still see the outline when the sun hits it right.

Try a little transition fluid on a rag. should bring back to normal color. you may have to do it twice a year.

Thanks guys, was able to mess around with a few areas tonight. Got some serious work ahead of me between polishing all the aluminum and trying to make the skins look nicer. Cannot believe people spend that kind of money on something and just neglect it. Good thing the inside is very nice!

Ummm... didn't you just spend money to buy it "neglected"?

Dennis12 wrote:
Try a little transition fluid on a rag. should bring back to normal color. you may have to do it twice a year.

This actually worked great! Hopefully it lasts for a couple months. Tried wax, polish, tire shine and a few other car tricks to no avail. Threw some transmission fluid on a rag and it looked new. Thank you Dennis!

Got one side done and the rear done today. Hope to finish the laminate exterior up tomorrow and start on polishing the aluminum during the week while waiting for rims, led lights, stainless door holds and brake assembly's to show up. 2 weeks and we're taking it out for the first time.