Understanding Brass Chem Cleans
One of the most common repairs we do in our shop is chemically cleaning brass instruments. I am constantly asked about chem cleans, so I thought I would use this opportunity to answer some of the most common questions.
What is a chem clean? Chem cleaning is a process by which a heavy degreaser, a mild acidic cleaner and detergent are used together to remove build-up from the interior walls of brass instruments. Some shops additionally use ultrasonic cleaning with chemical solutions, which does a good job, but it not necessary in order to do a good job. The chem cleans purpose is to clean and sanitize the instrument, as well as keeping pistons, rotors and slides functioning properly.
How often should I have a chem clean done? I always recommend to customers buying a used brass instrument to have it chemically cleaned before playing the horn. It is sanitary and starts you off with a properly working instrument. If you regularly bath your horn every few months, you can go several years without needing a chem clean. If you never give your horn a bath (which is common), a chem clean may be necessary every year.
Can’t I just give my horn a bath instead of having a chem clean? Bathing your horn is very important, however, I believe chem cleans are also a necessary part of caring for your brass instrument. There are mineral build-ups and biological deposits which occur in a brass instrument that soap and water alone cannot remove. If you bath your instrument in soap and water regularly, the need for frequent chem cleans will be greatly decreased.
How can I tell if my horn needs a chem clean? Sticking pistons, rotors or slides can be one possible sign. I recommend pulling the slide closest to the mouthpiece of the instrument and look inside the slide. If you see excessive green or brown build-up, it could be a sign you need a cleaning. On trombones and trumpets, you can pull the main slides off and look through the leadpipe (where the mouthpiece goes into the instrument) while holding it up to a light source. You should see smooth metal, clean looking, interior walls. More likely you will see food, mold and mineral deposits which should be chemically cleaned out. If you are still unsure, most repair technicians should be able to offer you a free assessment of your instrument.
How can I extend time between chem cleans? The majority of the buildup in the leadpipe area of the horn is food. It will help if you can brush your teeth, and/or not eat before or while you play. Also bathing your brass instrument in warm soapy water ever few months will reduce the need for frequent chem cleans.