I seem to recall they are made out of cork. I will have to go out and look at the piles of wiper motor assemblies I have.
This reminds of that Pace Picante Sauce commercial with the cowboys around the campfire and finally one says, "Get a rope."
When I find things like that, in my car or in the back yard, I tend to throw them away, not taste them for flavors
one time a big flake of something chipped off from undereath my car and you wouldnt guess what it was.. PEANUT BRITTLE!!