Oh dark-thirty (04:40) I dropped the key fob. Almost fell down a hospital'storm drain

but moisture will get in and effect the circuit board in it. I would put it in at least a zip lock bag. get the air out of the bag, wrap it around the fob and tape it up so its condensed. just a thought.

oh sorry missed the inside part.

Your idea is good. The key will probably rust.
A strip of electrician’s tape is folded over the metal part.
Will probably need to clean the key before use.

Even with the tape I would still go with Weekend Warrior’s idea.