Remove all removable parts from the trumpet. This includes slides, valve caps, valves, mouthpiece, and the lyre. Use extreme caution to not drop or allow the valves/pistons to bang together. Carefully wrap them in a towel and set them aside.
Step2
Run a warm water bath and soak the trumpet, slides and caps (no valves) for up to one hour. Do not add chemicals and the water should be cool enough to put your hands into comfortably.
Step3
While the trumpet soaks use soap and water to clean the mouthpiece. Scrub well with the mouthpiece brush. Rinse well and set on a paper towel to dry.
Step4
After the trumpet has soaked for a while scrub the inside of the valve casings with a casing brush. You can use plain water for this, but I recommend using rubbing alcohol which will help break up the built up oils.
Step5
Use a snake brush or other long thin cleaning brush to scrub out the inside of the lead (mouth) pipe. This is an area that builds up with "gunk" and should be cleaned often. Using a cleaning swab after each time the horn is played will help preven buildup, increase the airflow capacity of the lead pipe and extend the life of the lead pipe by preventing corrosion.
Step6
Using the snake brush, or another long thin cleaning brush, scrub out the inside of all tubes and slides.
Step7
Re-grease the slides and install them. Install the valves and oil them properly. Your horn has been maintained and is ready to play!