Can you "kill" a millenium bypass circuit?

[superferrite]

I had one working fine, but it stopped working when I tried to stuff it in the (metal) enclosure.
Could I have killed the BF120?

[Mike Burgundy]

Possibly - it is a MOSfet, and they tend to dislike static discharges. That said, discrete transistors are usually quite sturdy, I've *never* blown one up by handling it (I did in many other ways  ), and never took special measures to deal with them. I'd suspect solderjoints and/or shorts first.
Have you taken it out again, to see if it still works? If so, look for possible contactpoints for shorts, broken joints, etc... If not, replace the fet.