You have a row of break-away pin headers for your electronics project, and you need to cut off a few so that they'll fit in your project's circuit board. I'll show you how to successfully get a nice cut.
Step 1: Sacrifice a header and pull its pin
Count off the number of headers you need, then count one more. You'll sacrifice one header in order to avoid the risk of shearing the insulation off a header you want to keep.
Use pliers to pull the pin out of the sacrificial header.
Step 2: Cut through the sacrificial header
You now have an empty socket, which you can easily cut with wire cutters. Cut down the middle of the empty header. (If you aim for the groove between two headers, you're instead likely to shear too much plastic off a header you want to keep. She says, from experience.)
Step 3: Done!
Finished and ready to solder.