If plastic is hard XIM I believe is a good primer for it, Krylon makes a
plastic paint in spray, Go to a real paint store not a box store, even
for autos there is plastic paint. Cleaning is key, likely alcohol
perhaps even something stronger like Xylene, and sanding with 400g if
its a glossy smooth surface. Anything can be painted, even you
contacting Krylon , Dupont or Sherwin Williams tech dept will get you
the right answer. If it is solid and style is not bad paint it, it will
be the cheapest rout.