the best method for painting hard plastic for us has been to clean with the Sem scuff & clean, followed by the Sem plastic/leather prep. Then use the two step application of the Sem plastic adhesion promoter prior to coloring. As everyone else has said.....spray especially when using an aerosol when the humidity is low. Do not hold the can too far away and you should achieve good results. If there is a little "blushing" one can use their heat gun carefully to get rid of that.