A friend had a porcupine visit and it left a number of quills. I couldn't believe how sharp and pointy these things are. He gave me a bunch of them and they work great for cleaning hole jewels and holes in plates. I wonder if the old-time watchmakers used them? If you have access to porcupine quills, give it a try!

I sure hope your friend wasn't around when the porcupine visited!

I know they will go through a radial tire.

Tom