Going to sound crazy but do it in a blasting cabinet. Done several synthetic and wood stocks in prep for painting using a friends cabinet. He uses black oxide and turns the pressure down so we're not pulverized the wood. Result is lots of media through the nozzle at reasonable pressure and only takes a few minutes to clean a stock. Use a test piece of soft wood to make sure no damage to the stock. Only areas that might need some attention will be the checkering. Give it a good spray with compressed air and wipe with denatured alcohol to remove residue.
