Whatever you use just make sure you follow the instructions on the can and also make really sure that the item is very very clean and clear of any grease and oil (including fingerprints!). Don't lay it on too thick and you let it dry off for at least the recommended time. Have seen just as many good results as bad, possibly more to do with the amount of preparation put into them. Some people swear that a very small amount of thinners in a large rag very lightly wiped over whatever it is you're about to spray is very good in getting the surface tacky enough for the dye to take well to. I wouldn't recommend getting to heavy with the thinners though as you may find an adverse reaction with the plastic trim if you do...