Originally Posted by Smokin' D
Bought a used Lang from that same guy! I got some oven cleaner and plastic bags. Sprayed the grates and put them in the bag, so the cleaner would not dry out, for a day or so. Took them out hosed them off and gave them a scrape. Repeat the process. When dry hit them with a wire wheel. Re-season and they were good to go.
Never tried this with expanded, but using this method every year or so, I am still using the original 35 year old grate on my Weber kettle. The plating is mostly gone, but oiled it still cooks like new.