How can I achieve a rusted look on the 8 ft. Corrugated Galvanized Steel 29-Gauge Roof Panel?

Here is some info to achieve a rusted look.

Spraying the panels with a saltwater solution from an insecticide sprayer and letting them sit outside will kick off the corrosion process. Then washing them off before it reaches the look you are after is the key as it will continue to corrode. We do not recommend doing this for an outdoor installation (it will rust soon enough in most cases), but for something like an accent panel indoors it works well.