Cleaning Fired Brass Cartridge Cases

Are you a recreational shooter who wants to reuse his fired dirty cartridge cases?

Whether you want to save money or just get the satisfaction of repacking your own ammo, you know that you have to make those cartridges perfectly clean for an accurate firing result.

Over the years shooters have used a variety of methods to try to get their cases back to that straight out of the box look.  Enthusiasts have tried tumblers, electric drills and all sorts of caustic concoctions. More recently, the move to ultrasonic cleaners has gained momentum.

Ultrasonic cleaners have a number of advantages over these other brass cleaning methods:

  • Low operating costs  – electricity cost for ten hours operation is only about 25 cents
  • Kind to the environment – do we really need any more toxic chemicals around us when we’re cleaning, and where do we put them when the cleaning is done?
  • Simple to use
  • Clean and relatively quiet (just try talking anywhere near a vibratory tumbler)
  • Quick, yet thorough, and most importantly
  • Safe – certainly perfectly safe, compared to the hazards to your fingers and hands from cleaning with an electric drill and wire brush!

Using ultrasonic cleaners, shooters have cleaned, restored and reused cartridges that have been fired four, five, six, or even more times.  And what´s more, shooters claim these carts are as good as new.  We have seen the results ourselves and have no doubt that the claims are true.  So, what’s the procedure?

Step 1 Gather the Ingredients and Tools

You’ll need the following items:

  • an ultrasonic cleaner (preferably 100 Watts power, but machines of 50 Watts will still do an acceptable job, if a bit slower to get there)
  • vinegar solution (half water/vinegar)
  • dishwashing detergent (any brand, but we use Morning Fresh – only a squirt will do)
  • Pyrex or glass beakers x 2
  • baking soda – you need to neutralise the acid in the vinegar after cleaning – this is important.  If you skip this step you may start to de zinc the brass.
  • distilled water – to rinse the cases off, so they can dry without marks or deterioration from the chemicals in the tap water
  • hair dryer/oven (not microwave)
  • your already fired cartridge cases, of course.

Step 2 Setting Up

Detailed instructions for setting up your ultrasonic cleaner are available if required.

  • Put aside your fired cartridge cases.
  • Set up your ultrasonic cleaner in a safe place, well away from traffic areas.  Many shooters already use a shed or workshop away from the living zone of the house (legacy of the noisy tumbler).  This is a good place to stay, especially if you want to keep this gear away from children.
  • Fill cleaning tank to about 2/3 level with normal tap water and insert the cleaning basket and just a single drop of dishwashing liquid.  Into the beaker pour the vinegar solution plus a tiny drop of dishwashing detergent, up to about 2/3 level – you will need to leave space for the cases that you will put in later (obviously the cases will displace the vinegar solution).  Don’t worry. The ultrasonic waves will pass unimpeded from the tank water, through the beaker, and to the cartridge cases to perform the cleaning you desire.
  • Place beaker inside the tank basket, making sure you top up the water level in the tank to the MIN water level mark.   Damage to the unit’s heater pad can occur if you allow the water level to drop too far. NB Many units will show the recommended MIN liquid level for safe operation.

Step 3 Doing the Cleaning 

  • Degas.   You want to make the cleaner run as effectively as it can.  This occurs when the tank is at the correct temperature and when the air has been removed from the liquid medium.  If your ultrasonic is heated, set the temperature at 60C.  If your tank is not heated follow the instructions in our blog.  Then run the cleaner through a normal cycle of between 5 and 10 minutes. The dissolved air should now be purged from the tank, so the ultrasonic effect can clean as well as possible.
  • Cleaning Cycle 1.  Add your fired cases to the beaker – carefully, since the tank will be hot.  Run the unit through a full cleaning cycle (10 – 15 mins). NB While the cleaning cycle is on prepare the 2nd beaker. Add 1 tsp baking soda to 2/3 beaker of tap water and mix well.
  • Cleaning Cycle 2. Carefully remove the beaker from the tank and rinse the cases under running water (preferably using a metal sieve).  Note improvement in appearance of the cases before adding cases to the 2nd beaker, as ultrasonic cleaners do vary in power. You may sometimes need to return the cases to the beaker, for an additional run through the vinegar/detergent solution.  If you are satisfied with cleaning progress, add the cases to 2nd beaker and place inside basket. Run ultrasonic an additional 10 – 15 mins cycle. Remove the cleaned cases from the beaker and rinse under tap.  At this stage cases will usually be clean enough to repack.  If any residual contamination  is present (unlikely, but remotely possible) then return cases to the beaker, with tap water and run ultrasonic a further 10 mins. Make sure you turn the machine OFF as soon as the cleaning is complete and reset the thermostat on the heater to zero C.  This could save the cost of expensive repairs to your heater, or even the ultrasonic transducers, if the liquid level is allowed to drop too far.
  • Distilled Water Soak.  Soak cleaned cases in beaker for 15 mins.

Step 4 The Moment of Truth

Remove cases from beaker and strain with a sieve.  They are now clean and just need to be dried for reuse.  Shooters commonly use a hair dryer, conventional oven or a drying rack to dry the cases completely.  Your environment and circumstances will dictate what is best for you.

  • A drying rack is fine if the weather is warm, but even under ideal conditions it may take a couple of days for the cases to be completely dry.
  • Oven drying is a great way to dry quantities of cases, and it is quick.  You should be able to completely dry several trays of cases in 45 minutes at 100C.  Just avoid trying this in a microwave oven.
  • Hair Dryer works well, especially for small batches, but a bit fiddly for serious quantities.
  1. You can streamline the process by using Cleaning Cycle 1 as your degas step.  This first cycle won’t be quite as effective as later, but it will still be very good.  Anyway, you are paying for the electricity – you may as well put it to use.
  2. Cleaning cycle times are estimates only.  How many cartridge cases you can clean in a given timeframe will vary from machine to machine.  It depends on tank capacity, power (wattage) of the unit, and of course, the size of the cases (the more volume per case the slower cleaning will be).  The more powerful the unit the more cases it will clean at the same time, but of course, the tank has to be big enough to hold them.  If you overload a machine with dirty cases you will quickly notice a change in the sound of the cleaner in operation (it will sound ‘dead’ as it becomes overloaded).  As an experiment, try running your ultrasonic with just plain water, then listen for the difference in sound when you add a large rock or house brick.
  3. Typically, the power of an ultrasonic cleaner increases in proportion to its tank capacity.  However, you can sometimes find a large unit which is quite under powered.  A tank of 2L capacity will appear underpowered with a 50 Watt transducer.  At 2.5L we recommend 100 Watts, and over 3.5L 150 Watts.
  4. The smaller type of plastic ultrasonic cleaner can still clean cartridge cases effectively.  However, these units are generally designed to have a break between cleaning cycles, otherwise the transducer could be overtaxed and fail.  You can still use them, but you need to recognise their limitations.  Follow the user instructions and your machine will last longer.
  5. The procedure provided in this blog has been tested by shooters in Australia under normal Australian conditions.  The products required to perform the cleaning process are readily available and cheap.  They are also safe to operator and the environment.
  6. If you have bought a new machine to clean your fired cart cases we recommend you test it first.  Click here for our blog on testing the function of an ultrasonic cleaner.  NB We strongly recommend the use of a surge protector to prevent power spikes damaging your ultrasonic cleaner.
  7. Just to recap – don’t forget to add baking soda as per procedure.  De zincing of your brass looks ugly and might even be dangerous when you shoot.  Take care of your gear.
Liquid Glass Oz designs quality ultrasonic cleaners for commercial operations in Australia and New Zealand (N18973)