Extra incorrect key fob useable?

[baconisafruit]

Long story short, I bought from Carmax ~3000mi used and the 2nd key was not for my vehicle somehow. Carmax paid for a new one and all is good. Now I have this 3rd fob and physical wrong key. The tech said it's now no good and can't be reprogrammed - is that true as that seems strange? Wondering if I should trash it, sell it/give it away, or save it for the future in case I need a new one. In case anyone is wondering, it's about $175 for a fob (significantly cheaper than expected), $25 for the hard key blank, and after labor (program and cutting) it was $380ish and took about an hour wait including some OTA updates.

 

[saleen032]

Once they are programmed to a vehicle, they cannot be re-used until they are unlocked. A dealer cannot do this though. Some locksmiths may be able to do this as special equipment is needed....