With the Metalprep and a Scotch-Brite pad, I completely stripped the rust from the outer body of the Jeep in less than an hour. I was absolutely amazed at how well the chemical worked. To mix Metalprep is simple: one part product and two parts water. Scrub the body for 1 to 2 minutes and rinse off. Repeat if necessary. I scrubbed in sections, rinsing each with fresh water.