My Grandson's trumpet teacher says NOT to put the trumpet in water, because it will "wear off the laquer." We cleaned it about a month ago by: Buying a cleaning kit from music store. Removing all the slides, valves and valve caps. Filling the kitchen sink with 6" of lukewarm water and a few drops of dish soap Putting the trumpet componets - except for the valves in the sink. Letting it sit for about 15 minutes while we cleaned the valves and caps by hand with a brush and some of the soap in the sink. After 15 minutes, removed trumpet compents, ran clear warm water thru horn and slides until soad removed and then ran a snake through all the components. Wiped off part of exterior compents with a soft cloth. "Polished" a bit with polishing cloth from cleaning kit. So, is the trumpet teacher right or is the process as described above OK?