I just bought a new smoker that has cast iron grates. I read about how to season them which I have done before with other cast iron pots and stuff. The directions say not to use a brush to clean it or you would have to re-season them. How are you supposed to clean a cast iron grate then?

While the grate is still hot, I always use a regular bbq grate brush and clean it. Then I get a paper towel soaked in olive oil and coat the grate real good.

I guess in a way you are kind of seasoning it each time.

Works for me and most of the people that I know do it this way.