I have used liquid car wax. Put a little on a microbrush, apply it to the affected area, gently swab around, then carefully wipe off. You will have to wash the canopy with warm soap water after that, as the wax residue will make any additional masking work difficult. Don't get any wax on the intentionally painted areas.
Easy Lift Off (ELO) will also work. Remember to test on a spare part first!
HTH, and good luck.