LEVEL THE MOUTHPIECE TABLE
You'll need a sheet of glass (a mirror works fine) which for the purposes of our discussion we will assume to be quite flat and level. You will also need a sheet of 600 (or finer) grit emery paper. Lay the emery paper on the glass, abrasive (dark) side up. Now, using a VERY light pressure, rub your mouthpiece from left to right across the paper, doing two strokes and two strokes only. Take a look at your mouthpiece table: if you see some shiny spots, they represent high spots on the table. Those high spots seriously affect response, and they have to go! Using light pressure, stroke your mouthpiece on the paper until the table is nice and even. Almost all mouthpieces have uneven tables, and this is a very easy cure. While you're at it, flatten the portion of your reeds that contact the table as well. This will guarantee a good seal, and your mouthpiece will play much better.
LAP YOUR NECK
Over time, the male tenon of your neck becomes uneven. Assuming it fits the reciever to your complete satisfaction (nice and tight), our goal is to eliminate high spots and irregularities. First, wipe off the tenon and the interior of the receiver. Now, apply a very small amount of key oil to the entire surface of the tenon and receiver. Apply a miniscule quantity of (1) lapping compound (I know you may not have this), (2) automotive buffing compound, or (3) abrasive toothpaste (regular Crest is good) and using a light pressure, rotate the neck 360 degrees in the reciever. Take it out and wipe all the surfaces off completely from time to time. You may need to re-apply the lubricant. You'll notice some shiny spots. Those are high spots and they cause leaks. Lap until the surfaces are completely smooth. Be sure to clean off all the oil when you're finished with this process. Leaving oil on the neck attracts dirt, grit, and all sorts of other nasty stuff which will cut into the surfaces.
CLEAN OFF YOUR TONE HOLES
Take some 600 grit emery paper and cut into strips that are one inch wide and about four inches long. Now, starting at the top of your horn, insert the strip with the abrasive surface toward the tone hole between the pad and the tone hole. Close the key with pretty good finger pressure and draw out the strip. Repeat until you have drawn the strip against the the fullo 360 degree perimeter of the tone hole. This will remove the gunk and build up that causes sticky pads.
TAPER YOUR NECK RING
Take a small very fine tooth file and taper the ring at the small end of your neck (where the mothpiece goes) until it has a nice edge rather than a vertical surface at the point it enters the mouthpiece chamber. This will reduce resistance and improve response.
CLEAN OUT YOUR OCTAVE PIPS
The octave pips are the smallest openings on your horn, and they tend to accumulate all sorts of unknown materials that you blow through your horn while playing. Take an ordinary pipe cleaner and clean them out monthly.
LUBRICATE YOUR SPRING CRADLES
Use a heavy oil or grease and apply a drop at the point where your needle springs contact the cradle on the rods. This will significantly reduce key noise.
ROTATE YOUR BUMPERS
On most horns, the felt bumpers used to stop the Eb, low C, low B, and low Bb are held in small adjusters which screw into the key guards. Over time, the ends of the felt bumpers wear and compress, and they no longer contact the key face with 100% of the available surface. Using a large screwdriver, rotate the bumpers just enough so the surface of the bumper completely contacts the key.
