Inside the Ultra-Secret Club That Knows WD-40's Recipe

Membership in one of San Diego's most private clubs comes with no bar, no food, and one perk: a glimpse of the recipe for WD-40. Only a handful of people worldwide have seen the full, handwritten formula for the 70-year-old lubricant, which is used for everything from loosening rusted bolts to getting gum off of turtle shells. As the Wall Street Journal reports, entry to that inner circle requires nondisclosure agreements, a special key controlled by the firm's top lawyer, and a visit to a concealed Bank of America vault where the notebook with the recipe is stored. CEO Steve Brass, who joined WD-40 more than 30 years ago, was allowed in only about 18 months ago. "It was like getting into Fort Knox," he says.

The notebook itself contains the successful "40th" water-displacement formula, as well as the 39 failed tries that came before it, plus at least one plain warning—"Do not smoke," recalls finance chief Sara Hyzer, who viewed it alongside Brass. Even senior scientists are kept out. Meghan Lieb, who's been at the company for two decades and is now head of R&D, still has never seen the formula and works from a coded version instead. She says her own family likely assumes that she must know what's in it, but she swears she doesn't. Hopefully no one takes a giant eraser to the notebook, either, as the Times of London noted a few years back that the recipe is scrawled in pencil.

Outside the vault, speculation is constant. Online forums debate ingredients—fish oil, citrus, coconut, vanilla?—with WD-40 officials knocking down the more popular myths. A past lab analysis by Wired captured some broad components, a company spokeswoman said, but not enough detail to actually reproduce the product, which still accounts for nearly 80% of WD-40's revenue. Reddit users now focus less on what's in the can than on what to do with it, trading thousands of ideas that range from detangling horse hair to killing wasps. As for expanding the secret club, Brass says he may add a few long-serving employees if the company ever reaches $1 billion in sales—but not, he insists, his own board.