You can't. They are undroppable so if you picked it up, you have to keep it. It is so that people can't trade them or hoard them and will have to go all the way to pick them up, without skipping most of the levels. The others, so far, are much farther down into the Undermountain (levels 10 and 12).
Just don't pick up two of the same one!
Welcome to Ironworks, btw!
[ 09-19-2006, 11:39 AM: Message edited by: Cloudbringer ]