If you don't want to spend $9.00 for the base coats, you can use any lacquer type paint for the base coat (most of the automotive touch up paints from Pep Boys are lacquer base).
I've used oven cleaner for years to stripe paint off of models. It seems to work best and doesn't ruin the detail on the model. I also use it to clean the model release off of new resin kits. Just spray it on, seal it in an old tupperware container over night (got my from a yard sale for $1.00), and clean it off with an old toothbrush, then rinse with water. You may have to do it two or three times, depending on the paint. Be sure to work in well ventilated area, and wear rubber gloves.