Try Breakfree CLP. You can get it at a gunstore or in the shooting supplies section of Walmart with the other firearm cleaners. It's amazing stuff. Once you try it you'll never use WD-40 as a protectant, cleaner, or lubricant again. Breakfree is another league.
From the manufacturer's site
http://www.break-free.com/?location=/products/index.asp
When the United States Military issued PD-48, a purchase description of properties for a single, multi-purpose product to maintain their weaponry, it became known as the "impossible specification" because of its severe requirements. The first product to meet the challenge - Break-Free CLP.
Break-Free's flagship product, CLP is a unique formulation of synthetic oils and individual proprietary ingredients which synergize in combination to do three important tasks simultaneously: Effectively Clean, Lubricate and Protect metal. After years of rigorous testing, CLP actually exceeded the Military's requirements and was approved as a product to meet MIL-L-63460, a new specification. Break-Free CLP is now recognized around the world as the standard by which maximum metal performance and protection is ensured.
* Penetrates and spreads along metal surfaces into every pit and crevice to undercut contamination and lift residue away where it can be removed.
* Long-lasting lubricating film dramatically reduces adhesion of sand, grit or other abrasives which cause wear and failure.
* Corrosion inhibitors prevent the formation of rust while Break-Free's unique boundary film protects metal surfaces from moisture and other contaminants.
* Specially formulated synthetic oils won't lose viscosity, dry out or stiffen up in extreme environments - such as cold, heat, dust, dirt, humidity and even salt air - keeping equipment in ready condition for months at a time.