I'm doing "Night of the Iguana". I want to do tin roofs on the cubicles. Home Depots got some great galvanized roofing. Unfortunately, it's REALLY bright and shiny. I want my dull, aged, and preferably rusty. Any suggestions? My only thought is to paint it with a flat glaze that's got some rusty brown in it. Any other ideas? Also thought about going after it with a grinder or sander to scuff it up and leave it out in the rain... but not sure how well that will work.