Huskybone, get on with your project. If you are making fair progress on your own and get stuck or have a question, PM me. I am not here to get you started though. I am sure that I could pass the course myself, but that is not the point here.
If you come up with a widget and want an honest opinion, you can also mail me details. I will sign a waiver up front saying that I will not use your idea for any commercial or non-commercial product. There will be no danger of stealing or disclosure to another party.
Cleaning a trumpet better requires:
1) mechanical safety (horn doesn't get damaged)
2) environmental safety (mother nature doesn't get damaged)
3) user safety (person cleaning doesn't get damaged - especially if a mess is left behind for mom to clean up)
4) higher convenience than using the sink
5) cleaner than using the sink and a snake
6) better user experience (this is tough as I really like caressing my horn while cleaning it)
7) cost effective solution
There are many solutions that fit these parameters. A bit of googling should make them apparent. I think this could end up being more chemistry than engineering though.