I used the hole in the end of a bottle opener as a washer once. My radiator hose had bulged and was spewing coolant at the end where it connected to the radiator.
So I pulled off the clamp, sawed off the bad part with a pocketknife, then put it back on but in the process dropped the washer that was part of the clamp under the car. I was in the office parking lot and couldn't find the darn thing as it was getting dark.
Luckily the bottle opener worked fine until I could get another clamp for it. It's always good to have a lot of miscellaneous crap lying around in the car, you never know when you're going to have to McGuyver something out of it.
LQ
Amazing what we can come up when we have to!