Trim back the affected wire(s) past the point of burned insulation - usually about 3-6 inches.

Install new lugs. These can either be soldered (if you have a powerful soldering iron, 65 watts or more, like a TS100 running on a 6S LiPo), or crimped if you have the tool to do it. Lugs can often be found in the electronic tools section of a hardware store - buy ones to fit the 10 or 8 AWG wires and the #8 screws.

If soldering, note that burned wire doesn't like to take solder - it will take a good amount of flux to do it, and it should be fully "wet" when done properly.