Clearing up muddy tone caused by excessive pucker or too much lip in mouthpiece. This may seem a foreign concept to some and remain so afterwards. if so? My words may not be meant for you. Everyone plays differently. While there can be similarities of muscle usage not all trumpet players utilize the same flesh/muscle lip/motion/positioning. In my own case this lesson took a while to learn. Throughout all my early lessons I was told to "always pucker" my lips into the mouthpiece. In some ways I feel fortunate to have been taught this as I could easily have fallen into some bad habits. The "smile" system was much more prevalent in my younger days. So because I puckered more I developed a respectable upper register fairly young while others did not. Then came the time back in '76 or so when a noted mouthpiece maker advised me to "clear the piece". Meaning: To clear excessive lip flesh OUT of the mouthpiece in order to open up the tone and get a BIG sound. His words were applied to to the use of shallow mouthpieces. In these shallower pieces excessive lip flesh can mussy the tone, reduce volume, worsen endurance particularly in the lower register. Lower register endurance and tone problems are common to those new to shallow mouthpieces. However once you've "cleared the piece" the tone can be fuller than your that of peers who use larger mouthpieces. reason: mouthpiece and chops working more efficiently. It is my belief that most all beginning, intermediate trumpet players are using mouthpieces that are far too large for them to support. Either due to lack of chops or undeveloped/discipline air support. So give them something easy to blow. Schilke "B" and "A" cups a good idea. Nothing really small (NOT like the 6a4a) until they develop more. But just something to assist tone production, lessen "clams" and make the music less of an effort. More fun in other words. And this is where "Clearing the piece" can be helpful exercise. A simple task, it can be learned in about a week and the student (if he learns to support his sound with lots of air) will sound far better. I've seen mere middle school bands adopt this idea and (other than their usual weak intonation) start to sound almost professional. But "clearing the piece" exercises are likely controversial. At first glance those unfamiliar might regard them as encouraging a "smile" or lip stretching concept. However this is untrue. Just the usual knee-jerk reaction. More later for those who want to hear about it. This is also a great way to blow a better sound on the low brass instruments. Especially for trumpet players who double.