[solids]

[ QUOTE ]
How to unlock your 3-digit briefcase combo if you forget it

[/ QUOTE ]

Step 1: Try the technique described in the OP.
Step 2: When it doesn't work, giggle the piece of can some more, curse, and slam the briefcase down.
Step 3: 001
Step 4: 002
Step 5: 003
Step 6: 004

...etc.