1 Use spray paint to cover large, flat surfaces of ABS evenly. 2  Always test the paint on a small area of the ABS before completely covering the object. 3  Watch to see if the paint reacts in any way with the plastic; if it does not, continue painting. Even if your paint is specifically designed for ABS, impurities in the ABS itself can cause a reaction. 2  If the paint and plastic do react to each other (the plastic may disintegrate, or the paint might streak and refuse to stick), clean the wet paint off the ABS and try a different kind of paint.