this from the original instructions
STEP 4:When preparing the Sun Shield for final painting, the under side of the shield should be masked as show above, to preserve the dull green finish which has been baked on during manufacture. The under side should remain green since this has been scientifically determined as the color which absorbs the maximum amount of light, and therefore provides the greatest protection from sun glare. No further prime coat is necessary before applying finish coat to match the car. We suggest the use of synthetic paint rather than lacquer as a finish medium because of its greater durability. However, the prime surface now on the sun shield will take either a lacquer or a synthetic enamel finish equally well. The surface of the various parts of the sun shield must be absolutely clean before application of the finish coat. Grease or other finger marks on the surface may result in blistering or peeling of the finish coat upon drying. To clean, we recommend that the shield be wiped with a clean cloth which has been dampened with naphtha. After wiping, allow sufficient time for the naphtha to evaporate before painting. Painters are cautioned to make certain that there is no moisture or water in the air lines leading to the paint gun, as a film of lacquer or paint containing small droplets of water will blister upon dry
