I would use caution when applying any degreasing agents on my RV's decals. The very nature of the decreasing agent would likely damage the gluing material used to apply the decals.
Not sure how alcohol or other agents would react to vinyl or plastic (petroleum based) decals or on gel coat surfaces?
I once ruined a trailer by washing it with household dishwasher soap, it worked miracles removing streaks and dirt but after a few years and much to my surprise it curled and cracked the decorative decals.
My 2c worth.
Keep the shiny side up!
GPG