First, I keep mine covered or in the garage at all times. Second, I clean the ashes out every cook, as moisture and ashes=rust. Lastly, for the cooler parts I keep a wire brush and a can of paint, so if I see rust, I address it immediately before it starts to pit (hard to stop then). On the hotter parts, I use a light coat of Crisco several times during a cook. I used to use Pam, but it leaves a sticky residue, and Crisco gives it a nice cast iron skillet look. I like the results of peanut oil too.