Whatever you use, make sure the trailer surface is cool to the touch. Don't try it on one of your hot sunny Florida days.
The volatiles in the cleaner will evaporate too quickly, and you also stand a greater chance of paint damage. The trick is to keep the adhesive wet and let the cleaner soak in and soften the adhesive. Pick a cool cloudy day or in the late evening after the surface has cooled. Be real careful of the paint surface if you try lacquer thinner....and do NOT try enamel reducer!
Rodger