Undercoating Products

As soon as I bought my 2010 Avenger I removed each wheel and inner fender plastic cover, and sprayed the 3M spray-on undercoating in each fenderwell and then the floor from under the car. It was pricey, but I've done it to 3 vehicles now without any problems. Unfortunately I didn't do it on top of the rear frame under the rear bumper on the wifes 2006 Jeep Wrangler and now I will have to raise the body off the frame so I can sand and paint it in that area.