How to Safely Clean a Bullet Mould

© 2014 – Thomas C. Dugas


Bullet moulds are made of various materials, from soapstone to very hard steels.  It’s common to encounter bullet moulds made from aluminum, bronze, copper, and various grades of iron or steel.


Bullet moulds made from iron or steel can be susceptible to rust.  Rust is usually of greatest concern on a bullet mould when the rust affects the condition of the cavities.  Rust on the exterior of the bullet mould only affects the appearance of a bullet mould, not its function.  It is the condition of the bullet cavities that matters most on a bullet mould.


Why this article?


I have been contacted over the years by family members who inherit their parent’s estate and discover steel bullet moulds that they wish to sell.  Often these steel bullet moulds have rusted, and the family members desire to sell these moulds on various auction sites (such as eBay) for maximum value.  Unfortunately, they often attempt to clean the bullet moulds BEFORE seeking advice on how to properly clean them.  All too often the moulds were perfectly fine with a little surface rust that could have easily been removed with a low impact cleaning method, but instead, in their ignorance and impatience, they decided to use a high impact short duration cleaning method because “We don’t have time to waste, we have a lot of things to do and we need to get it all done as quickly as possible.”


I have lost count time number of times I have been offered perfectly good bullet moulds that were ruined beyond repair by the wrong cleaning method.  Some of these ruined bullet moulds were worth $500 or more before they were cleaned.  They are worth nothing when ruined.


To properly clean a steel bullet mould that has rusted, you need to first seek the advice of an expert BEFORE you clean the mould, not after.  It is a common occurrence when someone has used an aggressive cleaning method to clean a bullet mould and create several new problems that did not exist before they cleaned the mould.


A very important point: It is extremely easy to ruin a steel bullet mould by cleaning it too aggressively.  You need to clean slowly, and numerous times, with a low impact cleaning method to safely clean a steel bullet mould.


You should consider the following chart when seeking advice on how to clean a bullet mould.  The left side of the chart is a short duration very aggressive cleaning method.  For example, a very effective way to permanently ruin a bullet mould is to use a wire (bronze) cleaning brush with a power drill to rapidly spin the brush inside the mould cavity to try and clean the mould in under 10 seconds.  There is a high probability, almost certain, that you will permanently ruin the mould should you choose this method.  Never, ever, use any metal implement to clean a bullet mould.  Metal on metal cleaning contact is the best way to permanently ruin a bullet mould.

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USGI Weapons Cleaning Toothbrush & Dawn Dish Detergent…great to clean moulds with…


The right side of the chart is long duration low impact represented by the green square.  This is the best method for cleaning a bullet mould.  With long duration, low impact, you are trading time to minimize the impact you have with your cleaning method and ensuring that your method is the least impact method to use to clean the mould.  The lowest impact method I use is a green G.I. Weapons cleaning toothbrush and Dawn Dishwashing Detergent.  Scrub the interior and exterior of the bullet mould with the toothbrush and dawn detergent multiple times.  Use hot water and effort.  Try to clean the mould at least ten times with this method before you decide to get more aggressive.  If the dawn detergent and toothbrush does not clean the mould to create a useable bullet mould, try using a good tartar control toothpaste in lieu of the dawn detergent.  Tartar control toothpastes contain mild abrasives, usually volcanic pumice, which will help remove rust and minimize the impact on the steel of the bullet mould.  Again, try cleaning the mould multiple times before you give up.  With a low impact long duration method of cleaning, it takes time to see incremental improvement.  This is the safest way to clean a bullet mould.


Review the chart below.  The lower right method is best, you are trading time and effort to minimize the impact of your cleaning method.  The upper left red box is the wrong way to clean a mould.  If you are impatient, and you cannot spend the time to properly clean the mould and you must use a high impact, short duration cleaning method, you will quickly speed past the point where you have removed all the rust that you can safely remove and enter the area where you cause permanent and irreversible damage to the mould.




Final Points:



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