Tumbling brass casings with stainless steel pins, water and a little soap is one of the most effective ways to clean them. The pins reach inside the case and leave the brass bright inside and out. Here’s how to do it in a rotary tumbler.
What you need
- A rotary tumbler with a barrel just for brass. Never use a barrel that has held grit, and keep this one away from your stone tumbling.
- Stainless steel pins (.047″ × .255″): 304 stainless, sized for cleaning brass casings, and reusable for many batches.
- Water and a few drops of dish soap. Many people also add a small pinch of citric acid powder for extra brightness.
- A colander or media separator to sort pins from cases.
- Gloves and old towels.
Step by step
- Decap first, if you can. With the spent primers removed, the pins can clean the primer pockets too.
- Load the barrel: about 1 lb of pins for every 1 lb of brass. Don’t overfill it, since the load needs room to tumble.
- Add water and soap: enough water to cover the brass and pins, plus a few drops of soap.
- Run 1 to 4 hours. Check after an hour. Heavily tarnished brass needs longer.
- Separate the pins: pour the load through a colander or separator over a bucket, and check every case. Pins can stay inside. 304 stainless is not magnetic, so a magnet won’t pick them up.
- Rinse and dry thoroughly before storing or reloading. Spread the cases on a towel in a warm, dry place until no water is left inside.
Stay safe
- Spent primers leave lead residue on brass and in the tumbler water. Wear gloves, wash your hands afterwards, and don’t eat or drink while you work.
- Keep the tumbler and barrel out of the kitchen and away from food.
- Dispose of the dirty water responsibly, not on gardens or down storm drains, and follow your local rules.
Keep your pins working
- Rinse the pins after every batch until the water runs clear.
- Store them dry, or covered in clean water, so they stay bright.
- Never let steel shot touch tumbling grit. A single grain can scratch the brass.
Steel shot works on jewelry, coins and other metal too. See our steel shot guide for which shot to use for each job, or shop stainless steel shot.