I didn't know there was such a thing! I would also like to find out more, being an oboist!
QUOTE(AnotherPianist @ Apr 21 2006, 12:04 AM)

I'm sure I read in a theory book somewhere that oboists achieve mutes by sticking handkerchiefs down the end of their instruments

.
I also read somewhere that oboists achieve A below the stave by putting a toilet roll in the end...
I tried it, but I had to cut the toilet roll then sellotape it, so it sounds horrible...