I use a rubberised plastic pen barrel, something like a Paper Mate, with the bit pushed very hard into the open end. This works well because the plastic's not the kind that can shatter. I had to shave it down slightly because the Torx bit made the end of the pen flare out so it wouldn't fit the holes. On a machine I've not opened before, I have to use pliers on the end to start the screw turning. When I reassemble, I only put the screws in finger-tight with this tool, so if I need to I can get them back out again without needing the pliers.