Hiding a spare key?

[Kiwi_ME]

I hid my chip-type key inside the car to ensure it doesn't get damaged, then and attached a mechanical copy of that key under the car tied on with stainless steel wire (just to open the door.)

 

[kb01]

Given how common license plate theft is, I'd be hesitant to hide a key behind mine.

 

[mechtech2]

Try Ace Hardware for a key case.