Here is something a little different than a tying tutorial. I learned this trick from Charlie Craven's book and can say it is way more fun than the old coffee grinder method. I have made some really cool dubbing mixes with this method. Take a look.
How to mix your own dubbing from Juan Ramirez on Vimeo.
Using a compressed air canister and a plastic bag, you can make any dubbing blend you like. It's fun and it's easy.