5gal bucket of hot Dawn water, nipple in, pump the hot soapy water through with a tight fitting patch, pour boiling water down the barrel, to rinse and dry it, remove the nipple, clean inside, spray with G-96, oil nipple and oil the treads. I fire a cap on the nipple to clear the nipple, before I ever get into the vehicle. Never fire a cap for cleaning, in the woods or at the range after arrival.