Unscrew the door hinges and move the door to a well-ventilated workspace.
Place the door on top of a protective plastic sheet in case of paint spills.
Mix 1/4 cup of trisodium phosphate (TSP) with 1 gallon of water in a large bucket. Once diluted, the TSP mixture won't be strong enough to irritate your skin.
Dip a rag into the TSP solution and wash the melamine kitchen door. TSP cuts through fingerprint oils and other residue common on doors.
Dry the kitchen door with a towel.
Apply bonding primer to the melamine door's surface, using a foam roller. If the door features any intricate details inaccessible with a roller, use a foam brush for these tight spaces. Bonding primer is a thick, high-adhesion primer. Foam rollers or paintbrushes provide the best coverage on slick surfaces.
Paint the door with oil-base or latex paint once the primer has dried. The bonding primer will have made the surface porous enough that a regular medium-nap roller or synthetic brush will work just fine.
Reattach the door hinges after the paint has dried.