Plugs Aren't Just For Hair: You Can Repair Tires

Ream Out the Hole in the Tire

In your tire plug kit, you'll see a tool that looks like a round file with a handle. This is used to clean out and rough up the hole in your tire prior to plugging. Take this tool and ram it into the hole. Move it up and down a few times to roughen up the inside. You don't have to go nuts on it, a few solid pumps should do it.