I spent several hours a few weekends ago cleaning all the rust off the outdoor griddle. Ended up using 100 grit sandpaper, it was just too far gone. The cover had somehow developed a leak and actually held water on the griddle surface.
I did a liberal seasoning with olive oil. Need to get some bacon and hamburger patties out there to finish that up!
Cut some wood to sit about 1/3 in from each edge, to keep the new cover off the surface, and hopefully shed all the rain we get here