If you have trimming to do--let's say you have a curve on the tip--what you want to do is just nip away, kind of crunch away a little bit at a time. Work your way up to the cut line. And to clean this up, use what I call a tile file. It is a carbide imbedded piece of steel.
For the bigger jobs, use the snap cutter; there is a carbide embedded wheel on the bottom of this handle. To use the cutter, simply slide the tile in place, scratch the wheel across the tile, pull it back to the middle, and hit the knob with your hand.
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