LPS 3 is a brand name for paralketone. Paralketone is a fairly thick oil based substance that sprays on and then dries to a soft waxy coating. It will keep stuff preserved for years. I lived in south Florida for many years and kept all my guns (the ones I didn't shoot on a regular basis that is) liberally coated with LPS 3 in plastic bags. I live in Arizona now, and some of these guns I'm looking at again for the first time in 25 years and they are fine.
Paralketone is a corrosion protectant used in the bellies of aircraft and also in boats. LPS is only one of many companies that make it. If you Google "paralketone", you can find other vendors that sell it.
You can buy it at your local Ace Hardware store or they can order it for you if they don't stock it in your store. It's not cheap, but it keeps guns rust free for decades, and is an easy clean off.
Last edited by gyvel; February 25, 2012 at 10:46 PM.