I do them about the same as my DO's. I take a strip of the cotton belting that is used to make dress belts with, sorry don't know the official name. I put a strip under the lids of my DO's and I put a strip between the halves of my pie irons. I then use a a tie to keep the iron halves together.
My theory is that the cotton will wick away moisture and keep the units open to air circulation. I've been doing this for about 20 years on well seasoned CI and never had any rust, so it seems to work.