Won't Clean

We got our Winnebago used and has the same stuff but the edges of the decals are going bad. When boat place said to wet sand it but that would tear up the decals. We tried beekeepers, 3 different cleaner waxes, rubbing compound, and polishing compound. Some with a buffer and some without. The part I washed and then scrubbed with 00 steal wool and then waxed looks best but like said above it will take a lot of elbow grease to do the whole thing.