Check this out. I stopped by a guys house near Birmingham several weeks ago looking at a car for sale and he just completed stripping the undercoating (and it was really thick) from a 70 Cuda. He used a rented steam cleaner and it took him about 6 hours. He sprayed it down with some type of citrus cleaner prior to blasting but it came out super clean and you can still see alot of the factory primer and marks. I took several pics because I was amazed at the job it did.