Sandblasting plastic is risky for the inexperienced. Professional clear coat paint is similar to epoxy based paint that’s mixed (resin and hardener) and is remarkably durable. Once the sandblasting chews through the clear coat and paint, the base plastic is extremely soft in comparison and the beads, walnut shells, or soda will abrade the plastic very very fast. It’s difficult to get a uniform finish. That being said, once all the paint is off, sandblasting leaves a really good surface for painting and, if applied properly, the paint and clear coat can cover a multitude of “oops” and overzealous moments with the sandblasted.