Clean the print with soap and water
Remove supports and trim excess material
Sand the surface with fine-grit sandpaper
Fill gaps or layer lines with filler or putty
Sand again until smooth
Wipe off dust with a clean cloth
Apply a primer designed for plastic
Let the primer dry completely
Sand lightly between primer coats if needed
Apply thin coats of paint
Let each coat dry before adding the next
Use acrylic, enamel, or spray paint suitable for plastic
Paint details with small brushes if needed
Seal with a clear coat for protection
Let the final coat cure fully before handling