The following is a set of instructions on how to safely and efficiently clean a trumpet. The methods described are those I have found to yield the best results.
Step 1: Before You Begin
Before you begin cleaning your trumpet you will need to gather and take stock of your supplies. You will need a "wire-snake" brush, a mouthpiece brush, petroleum jelly, valve oil, a lacquer polishing cloth or a silver polishing cloth (depending on your trumpet's finish), several towels, and non-bleach dish soap (Bleach can be corrosive to the instrument's finish.). These supplies are displayed and tagged above. You will also need to decide on a wash basin, such as a bath-tub (recommended) or large sink. The wash basin must have running, heated water and room for maneuvering the trumpet safely. Be prepared to apply only lukewarm water, however, and not water that is too hot. Very hot water could cause the trumpet's finish to flake. You will be reminded of this every step. Finally, acquaint yourself with the following terms if they're unfamiliar:
Bore - the interior chambers of the instrument that define air flow path
Lead pipe - the pipe connecting the mouthpiece and tuning slide; part of the horn
Bell - the final, conical section of the trumpet; part of the horn
Valve casings - the chambers that contain the valve pistons; part of the horn
Other important trumpet parts are depicted in the next step.