I have had a bad experience with rust so I keep a dehydrator on my engine that runs about three hours per day. It probably doesn't help cylinder walls much but I hope it helps the cam and lifters.
Another thing I do is blow the moisture out of the engine if I'm not going to fly for a few days (pic) This is a 12V air-mattress pump from Walmart (pic). When I turn this on, I will see 3-4 seconds of moisture come out the breather. That moisture, left in the engine, would condense on the cam and start corrosion, cam wear, and lifter spalling. A new cam is $800-1000, AMHIK.
Lycoming says run the engine for an hour and get it up to 180 degrees or more to evaporate water from the oil. Even if I do that I still see about the same amount of moisture blow out, so I know it must help.
Do a google image search for engine dehydrators and you will see some other homemade ideas. For me, the silica gel will last for at least six months, then I take it home and dry it out in the oven.