If they're Allen head screws you can also sometimes drive the next larger metric size into them if they're standard to start with. Depending on which standard size they are, often the nearest bigger metric will only be a hair bigger and will drive into the socket tightly with a few light taps from a small hammer.
Then, once you get them broken loose and free turning, tap the metric wrench back out with the hammer while the screw has still got most of the threads engaged so you don't end up with the dreaded "allen-screw-stuck-on-the-wrench-with-no-way-to-get-it-off" syndrome.
:evil:
Then, once you get them broken loose and free turning, tap the metric wrench back out with the hammer while the screw has still got most of the threads engaged so you don't end up with the dreaded "allen-screw-stuck-on-the-wrench-with-no-way-to-get-it-off" syndrome.
:evil:
