Just so folks will not do something silly with their can of WD40. Just cause the propane is gone does not make the product non flammable. I have seen many diesel engines started on WD40 since 1996. Plenty of gas ones as well. It is not a bomb anymore when for example it gets shorted out under a hood, trailer house, inside a dryer, flame, sparks etc. But it will still flame. It is still dangerous. It can still start a fire. It can still fire in an engine. Treat it like gasoline and you will be happy you did. Starting fluid has had lube in it since the first time I used it in the 70s. At least every bottle I tried did. I always looked. As far as starting diesel engines with it tractor trailer rigs, farm tractors, loaders, dozers, graders and about every other large diesel engine I have been around had a starting fluid port to screw a can onto and directions in the cab as to its use. My brotherinlaw would only use John Deere bottles.