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Chemical Case Cleaning Solutions

While tumbling cases in an abrasive media provides the best finish, extremely dirty cases can be decapped first (using a non-sizing die) and then washed in one of the following solutions. The final rinse in soapy water helps prevent tarnishing. All of these methods were approved by Frankford Arsenal and will not weaken your brass.

* A 5 percent solution of citric acid (available from your drugstore) and warm water for about 10 minutes. If your water is very hard increase the amount of citric acid. You can add some Dawn™ or Cascade™ dishwasher liquid soap (which does not contain ammonia–be careful some do), to the solution for extra grease cutting ability. Follow with a rinse in hot soapy water (Ivory™ works well) and allow to dry.
* A solution of 1 quart of white vinegar and 2 tablespoons of salt. Soak with some agitation for 15 to 20 minutes and follow with a rinse of soapy hot water and allow to dry.
* A solution of 1 quart of water, 1 cup white vinegar, 1/2 cup lemon juice, 1/4 cup laundry or dishwashing detergent, 1/8 cup salt. Soak with some agitation for 15 to 20 minutes and follow with a rinse of soapy hot water and allow to dry. This may leave brass with a slight pinkish cast which will disappear with a short tumble in media.
* Military arsenals use a heated 4 percent sulfuric acid dip with a little potassium dichromate added. The solution is heated until bubbles rise slowly without it boiling and the cases are dipped into it for 4 -5 minutes using a basket of copper screening or plastic. A final rinse using plain hot water is followed by hot water with Ivory™ soap in it and the cases are left to drain and dry. Because of the use of heated sulfuric acid this method is probably impractical for home use but is given here to show what can be safely used.

Cases which have been fired several times and which show signs of carbon build up internally can be rinsed in straight paint & varnish makers (P&VM) naphtha available at any paint store. Decap, soak for 5 – 10 minutes, drain, allow to air dry and then tumble as usual. Cases will be sparkling clean inside and out but not any shinier.

An interesting idea is to use an “air stone” and a small air pump from a fish aquarium tank to agitate the liquid cleaning solutions.

Thanks to Randy Wood for this tip.

Another case cleaning method is the use of an ultrasonic cleaning unit. These units are available from several online sources and the biggest problem is finding a reasonably priced unit with about a 2 liter capacity. While you can only clean small quantities of cases at a time this way they will be clean as new, inside and out. Once you’ve acquired the unit you’ll need to also acquire a glass beaker of sufficient size for your use and make a cover and beaker holder.

Cut a piece of Plexiglas to cover the tank and cut a hole the size of your beaker (use a fly cutter and a drill press or jigsaw it out). Make a collar for the beaker out of plastic foam that fits very snugly so the beaker can be raised or lowered. You want the beaker to not sit on the pan of the cleaner.

Fill the cleaner tank with water and by adjusting the level of water in the tank, the liquid in the beaker, and depth of the beaker in the water it can be “tuned” so that the liquid in the beaker appears to boil while the water in the tank is calm. This has a major effect on how long it takes to clean the cases.

For cleaning you can use either of these procedures but the second one leaves the cases the shiniest.
24 minutes – 50-50 Vinegar and water + 1 Drop Dish Soap per
8 ounces water Use cool water. Do not use hot water!!!
8 minutes – Baking Soda & water (1 grain BS per ounce of
water)
8 minutes – Hot Water
8 minutes – Distilled Water 24 minutes – 50-50 Vinegar and water + 1 Drop Dish Soap per
8 ounces water Use cool water. Do not use hot water!!!
6 minutes – Birchwood Casey Case Cleaner*
6 minutes – Hot Water
6 minutes – Distilled Water
* The Birchwood Casey case cleaner is listed as their “Brass Cartridge Case Cleaner # 33845”

This idea was originally presented on the 6 mm Benchrest site at http://www.6mmbr.com/ultrasonic.html by Jason Baney, and more info and test results are published there.