Hardware and Fasteners - How to cut (shorten) a screw and have it still be useable?

Is there a good way to cut a screw to shorten it and still have it be useable? I need to shorten the screws that come out of an electrical box that will hold my new lights to the box/wall.

After agonizing over the many details of my bathroom remodel, I realized when I went to put up the new lights that I forgot something. The electrical boxes for the lights are on the wall, mounted between the studs with braces.

When the walls were open, I checked to make sure that the screws from the old light fixtures were the right diameter for the light fixtures, but neglected to check how long the screws were supposed to be for the new light fixtures. Now the wall is closed up and painted, and I discovered that the screws are about an inch too long.

Electrician's wire stripper pliers have a means to cut 6-32 and 8-32 screws and dress the threads.
What size screws do you have?

Just be sure to insert the screw into the threaded side first, so your waste will fall out. When you remove the screw, it automatically chases your threads. Did it wrong once. You won't do it wrong again.

I use my rotozip with a metal blade. I cut the screw to length and then "Roll" the tip on the blade, kind of like you were sharpening a pencil. You only need to knock off a little bit of metal and your screw will work as normal.

The screws are 8-32 and it looks like my wire stripper pliers have the holes to cut the screws. I never realized before what those holes were for, since I only had to use it to strip wires. I'll give that a shot. Thanks!