17 years painting everything for a living. Pre pack propellants are fine if clear coated with laquer. 2 coat minimum.I suggest 4-5 coats. Then when the methane does dull or occasionally impart pink hue. You can easily rub it out with a quality polishing compound in a couple minutes. Also the newer synthetic automotive waxes are almost impervious to fuel for moderate amounts of time. Spent a few years removing diesel fuel stains from new heavy equipment parts until management accepted laquer clear coat. Then no more rework. Off road diesel is more corrosive than watered down nitro.