Re: striping metal cars...
1. Use pine-sol for as long as it takes (not usually too long).
2. When scrubbing, do it in a cup of isopropal. Do not scrub with water, it'll just make everything all gooey.
For plastic cars with factory paint, I don't know why anyone uses anything other than 91% isopropal. I've had issues striping my own paint jobs.
Jason