I have read a lot of very positive stuff about Q20 products. http://www.qmaxxproducts.com/

I really like this stuff.

"Boeshield T-9 was designed by Boeing Aviation as a corrosion inhibitor for aircraft components. Through licensing, this product is available to consumers and businesses. Boeshield T-9 is a combination of solvents, lubricants and waxes designed for penetration, moisture displacement, lubrication, and protection.

Boeshield T-9 dries to a thin waxy film that clings to metal. Because it adheres to metal so well, it works directly on exposed metal surfaces. The product can be used in two ways to prevent rust.

A thicker coating works in places where additional protection is helpful such as on hinges, chains, undercarriages, cables and on items put into storage. To apply a thicker coating, just spray it on and leave it.

A thin coating works well when direct contact is made with the surface such as on cast iron table tops, garden tools and other hand tools. To use a thin coating just spray it on and use a rag to remove the excess. Applications of T-9 every few months maintains the rust inhibiting barrier.

Unlike some sprays, it is safe on paint, plastics, and vinyl. As an added benefit it will also loosen rusty and corroded parts."

I too have coated my engines in WD40 for the winter. Could be equal, or better products out there like CRC etc, but bottom line I think is whatever is used for however long it lasts, is better than using nothing at all.