Sandblasting only gets your bumper partway down to bare steel. Stripping finishes the job: your bumper takes an acid bath that removes the old, scratched, pitted chrome from the surface and takes it back to bare steel. But bare steel rusts very quickly, so afterward we dunk your bumper in an anti-rust solution to prevent any oxidation from forming as it travels through the rest of the facility. The next of those steps is grinding.