We had two antique grilles to install in the half bath. The first is an antique we found to use as a thru wall grate to the radiator enclosed behind the credenza. The second is an existing grille from the old 2nd flr bathroom that was no longer in use, that we are using instead of the standard ceiling bathroom fan cover. We started out by sandblasting the gunk off, using a kit from the West Philly Tool Library. It was quite the experience:
Done and done!