I used pure denatured alcohol, from Lowes, to remove some unwanted decals that were on the RV when I purchased it. The process is slow but it worked well for me. I cut a red shop towel in 4 squares. Soaked a piece of shop towel in the alcohol and rubbed an edge until it started to loosen. Kept working that area until I could get a grip on the edge. By pulling the decal, keeping the contact point wet with alcohol working slowly I got the whole decal off.
Wayne, Diane, & Bentley (our 22 lb. alarm system)
02 Pace Arrow 37A-Workhorse, 01 Jeep Wrangler toad.