poke the screw through a piece of masking tape with the sticky side of the tape toward the head. Place the screwdriver in the slot, then fold the tape up onto the screwdriver. Once the screw is well started, pull the screwdriver loose and remove the tape.
Spin two nuts onto the bolt, tightening them against each other. Then chuck the bolt into the drill and hold a hacksaw blade against the spinning bolt. The nuts help to steady the blade and clean off burrs when you unscrew them.