My powder coated grill also rust at the edges. Contractor idiot never advise to get it galvanized.

I cleaned the rust area with wire brush, wipe it down with water. After it dried I just spray about 10 light coats of Rustoleum.

Lucky me the powder coat is grey. Bought Rustoleum in flat black from Ace hardware. Don’t really notice the color if you don’t go look for it.