Not sure if this can apply to the gas cap as well. But years ago I lost the ignition key to my Norton motorcycle. I called around to some locksmiths on my options. A guy in a van came by that afternoon with a device that had a large gauge on one end and some tiny fingers sticking out the other end. He stuck the fingers down inside the lock and twisted a couple of things. Then went inside his van for a minute and came out with a working key.
If you have a good lock wizard in your town, he may offer a similar option. Good luck.
@Sekal1978 The ebay ad shows "sold". Yikes, I should have asked for more $. As for the key, Have you taken it to a locksmith? I have seen a video showing the use of tool that looks like a fancy key that is inserted into the lock cylinder and then shows - duplicates the tumbler settings in a way that a locksmith can make a key.
@andylarry no man. You sold it just right. Not too expensive, not too cheap. That one was for sale for at least a year and you sold it in a couple of days.
Thank you @planetmojo2 (by the way who's planet mojo 1, lol)and @andylarry. will look around for a good auto locksmith.
Someone may want to devise a lanyard to keep these connected to the car when gassing up. Some of the rarity on these caps can be from resting it on the roof at a gas station and driving away without replacing the cap. I'm one of the guilty ones... but learned my lesson after the first experience.