Re: soprano mute?
Start with some wire, like a metal clothes hanger, or something similar, and shape it into a circle (your finished product will look like a donut). Wrap it with some cloth just to the size that it will fit into the bell. Now finish with some felt to make it look pretty. Mutes work great on alto, but it could fall out of your soprano. Another method is to glue some "mole foam" across from the low Bb hole (on the inside of course). This works great and never falls out, the only problem is that it is not removable like the donut style mutes.