I have been using different size and shape wire wheels on a grinder and a drill. There is a few pics of my oscillating multitool going to work too. Thing works wonders on the tougher undercoating and seam seal with less mess. I might need to use a bit of thinner in the front wheel wells and some other areas where the residue just wont scrape off. So far I have been trying the wheel and power scraper methods. Got some floor pan done too.