Pinched this from the VFR Forum...
Water Displacement #40. The product began from a search for a rust preventative solvent and degreaser to protect missile parts. WD-40 was created in 1953 by three technicians at the San Diego Rocket Chemical Company. Its name comes from the project that was to find a "water displacement" compound. They were successful with the fortieth formulation, thus WD-40. The Corvair Company bought it in bulk to protect their atlas missile parts.
The workers were so pleased with the product, they began smuggling (also known as "shrinkage" or "stealing") it out to use at home. The executives decided there might be a consumer market for it and put it in aerosol cans. The rest, as they say, is history.
It is a carefully guarded recipe known only to four people. Only one of them is the "brew master." There are about 2.5 million gallons of the stuff manufactured each year. It gets its distinctive smell from a fragrance that is added to the brew.
Ken East (one of the original founders) says there is nothing in WD-40 that would hurt you.
When you read the "shower door" part, try it. It's the first thing that has ever cleaned that spotty shower door. If yours is plastic, it works just as well as glass.
Here are some of the uses
1. Excellent for spraying on snow shovels for quicker release of load.
2. Then try it on your stovetop... It's now shinier than it's ever been. You'll be amazed.
3. Protects silver from tarnishing.
4. Cleans and lubricates guitar strings.
5. Gives floors that 'just-waxed' sheen without making it slippery.
6. Keeps flies off cows.
7. Restores and cleans chalkboards.
8. Removes lipstick stains. Just spray on clothing where the stain is located and wash.
9. Loosens stubborn zippers.
10. Untangles jewelry chains.
11. Removes stains from stainless steel sinks.
12. Removes dirt and grime from the barbecue grill.
13. Keeps ceramic/terra cotta garden pots from oxidizing.
14. Removes tomato stains from clothing.
15. Keeps glass shower doors free of water spots. And removes hard water build-up.
16. Camouflages scratches in ceramic and marble floors.
17. Keeps scissors working smoothly.
18. Lubricates noisy door hinges on vehicles and doors in homes.
19. Gives a children's play gym slide a shine for a super fast slide.
20. Lubricates gear shift and mower deck lever for ease of handling on riding mowers.
21. Rids kids rocking chairs and swings of squeaky noises.
22. Lubricates tracks in sticking home windows and makes them easier to open.
23. Spraying an umbrella stem makes it easier to open and close.
24. Restores and cleans padded leather dashboards in vehicles, as well as vinyl bumpers.
25. Restores and cleans roof racks on vehicles.
26. Lubricates and stops squeaks in electric fans.
27. Lubricates wheel sprockets on tricycles, wagons, and bicycles for easy handling.
28. Lubricates fan belts on washers and dryers and keeps them running smoothly.
29. Keeps rust from forming on saws and saw blades, and other tools.
30. Removes splattered grease on stove.
31. Keeps bathroom mirror from fogging.
32. Lubricates prosthetic limbs.
33. Keeps pigeons off the balcony (they hate the smell).
34. Removes all traces of duct tape.
35. Folks even spray it on their arms, hands, and knees to relieve arthritis pain.
36. Florida's favorite use is: "cleans and removes love bugs from grills and bumpers." Bug guts will eat away the finish on your car if not removed quickly! Use WD-40
37. The favorite use in the state of New York--WD-40 protects the Statue of Liberty from the elements.
38. WD-40 attracts fish. Spray a LITTLE on live bait or lures and you will be catching the big one in no time. Also, it's a lot cheaper than the chemical attractants that are made for just that purpose. Keep in mind though, using some chemical laced baits or lures for fishing are not allowed in some states.
40. Use it for fire ant bites. It takes the sting away immediately and stops the itch.
41. WD-40 is great for removing crayon from walls. Spray on the mark and wipe with a clean rag.
42. If you sprayed WD-40 on the distributor cap, it would displace the moisture and allow the car to start.
43. It removes black scuff marks from the kitchen floor and shoes!
P.S. The basic ingredient is FISH OIL