I made a protective case for my sandisk cruzer out of a chew can.

Step 1: Supplies

now to get the supplies

Your going to need the following:
some kind of harmless insulation foam, i used some left over acoustic foam i found.
and supper glue
optional, is you can find it, foam sheets, like 1/8" thick

Step 2: Main Body

ok now your going to construct the main body

first take the strip of foam and put it in around the wall of the can.
cut it to a good fit.

Step 3: Linings( With Foam Sheets)

if you have the foam sheets this is what you do.

ok trace out 3 circles approx. the size of the can a little smaller
although the third be a little smaller than the other two.

Now you glue the first one to the bottom of the main body of the can.
then put alot of glue on the first sheet in the lid, and glue on the third slightly smaller circle
the reason for it being smaller so it allows a good fit of the lid and body.

Step 4: Status

ok you should have the basic look of it.

now cut out slots for the thumbdrive to fit.
now glue the outside foam down to the bottom
and this is what you should have.

pic 2:
now see if the thumbdrive fits.
if not continue trimming away to make it fit.