Lee has a section on this in his book; interesting reading.

Yesterday I got out all my slot type mechanic's drivers and touched them up on the grinder; squared the tip, ground out the chips. I'll select an old one next and reduce the wedge to see how that goes with brass.

(There's a bit of a design prob with with a wedge shaped driver going into a channel slot. Good way to make a mess of the brass tote and knob screws on planes.)