These are the first ones I've restored but the process was simple. I used a small soda blaster to strip the old paint, tucked paper into the wheel wells to keep from painting the wheels, and spray paint. Now I need to find a few more colors for my other dug cars.
It's really easy, I use a $20 hand held gravity feed sand blaster from Harbor Freight, but I just use common baking soda as my blasting medium. It does a good job of removing the paint but doesn't rough up the surface of the metal. Then I simply tape off the wheels and paint.