humidifying tube

[Dorothy A. Bell]

Dear Friends,
Recently I have seen, in an institutional and in a private piano, a
device which was new to me. It is a plastic tube, white, about 3' long,
small long slits in the side, yellow end caps, filled with
I-don't-know-what absorbent material. The piano owners tell me that they
soak the tube in the bathtub till it is heavy, wipe off the outside, and
put it in the piano on the plate; they believe this provides needed
"humidity" for the piano. When the tube feels light (about one week)
they repeat the process.
Has any of you ever heard of this approach? Does it help the piano? harm
it? have no effect? I was a little alarmed when one customer said she
didn't remember the name of the person she bought it from but he also
sold clarinets.
Thanks for any input.
Dorrie Bell