I haven't had very good luck with paper clips. A better tool is a used dental
pick, because this is tempered and holds up when you put stress on the lock
with a tool (screwdrivers are not the best tools to use, as they can
dent/flatten the lock noticeably, but in absence of a better tool they work.)
Put the screwdriver in, apply pressure, stroke the lock pins with the pick.
If you're really into it, you grind and temper a thin tool with a bump at the
end. The computer locks I've seen (excl. IBM Medeco) don't need this,
though.'
-Scott Quinn