I wish there was a quick way to do this. Cockel burrs are easy but painful if you're not careful. Begger lice (triangular brown flat do-dads) are pretty easy to pick off but the dull knife idea above sounds interesting.
I pick em off in the stand and try to avoid them when walking out. I always take these clothes to the deck and pick em clean before putting them in the wash. Still, my wife will find a few begger lice in the washing machine or other clothes from time to time.
Of course the worse thing I ever did was to put some deer pellets in my pocket about 31.5 years ago (we've been married 32 years). That was the last day she ever checked my pockets before loading the machine! My mistake has cost me washed licenses, thumb drives, bullets, wallet, and even a watch. Of course when she held out those deer pellets and asked what they were, I wish I had been smart enough to tell her a bit of a story instead of the truth. Wood plugs wouldn't have put her off as much as deer turds.