thinking about this some more, apart from the muting aspect, which we have all covered in one way or another, except for this. The old fretless banjos were tuned a little lower, had gut strings, skin heads, not so bright a sound, that old-timey sound is what some of us are trying to get to by stuffing rags, socks, etc, in what has become by design a brighter, louder, resonating instrument. Better we all get old fretless banjos, gut strings, and tune down a bit?!

On the other hand, maybe this practice also came from trying to de-humidify the skin heads that were more common than they are today. If you stick a rag in there, it might wick the moisture, or act a little like the dehydrating packets that come in shoes, etc. Any thoughts on the practicality of this?