Oil or enamel paints are the best paints to use on plastic. These paints form a strong bond with plastic surfaces and do not wear off easily.
Enamel paint comes in spray cans and is a good choice for large plastic surfaces that require a lot of paint in one color. Oil paints come in tubes and are good for small projects and projects requiring detail work and custom color mixing.
Before painting a plastic surface, clean it thoroughly. Grease and debris keep the paint from sticking properly to the surface. If the surface is irregular, spray it with an even coat of a neutral color enamel paint as a primer, and then add the colors of choice.