They are likely 'dry rotted' by now & will rip apart or smear like crazy if you do need them.
Funny you mentioned the horn, went to use mine & it was in-op ! Relay was bad & it's back working now, but I don't use it often & have no idea when the relay blew. I do periodically cycle thru the Nav, cruise, modes (to exercise the adj. shocks etc,) just to verify it all still works. Guess I need to add the horn to the routine