If you do put some water in it, and then tip it back so that the water partly covers the inside of the spout, it will produce when you hum into the spout a warbling effect, or for us Aussies a didgeridoo effect with a larger pot. Amount of water, angle of spout etc vary the sound. It is advisable to remember to blow not suck, or you might get a lungful of water. This is on the same principle as the little ceramic bird warblers we had as kids like a whistle that you would put a bit of water in.

The pot lid also makes a wa-wa mute, which combined with the water-warble allows for some interesting combined effects.

The last mute I saw in action was the excellent Australian Youth Orchestra doing Shostakovich's 10th Symphony, which featured a tuba larger than the lass playing it. While this was diverting enough in itself, at a dramatic point she produced a kind of huge shiny UFO also bigger than her, and proceed with the showmanship and timing of a magician to insert it into the bell of the tuba, a feat only just physically possible. While Shostakovich no doubt had keenly intended the musical effect of the shift in tone, he had probably not intended the audience to be transfixed by the consequent spectacle for the previous eight bars.

Such the delights of unconventional instrumentation.

Cheers, Chris