Turn off water. Select a cutter head that fits the inside diameter of the retaining nut. Slide the retaining nut over the threaded shaft of the seat-dressing tool, then attach the locknut and the cutter head to the shaft of the tool.

Screw the retaining nut loosely into the faucet body. Press the seat-dressing tool down lightly and turn the tool handle clockwise two or three rotations. That should be enough to smooth the worn seat. Remove the tool and check the seat with your finger. If it feels smooth, reassemble the valve. Turn water back on.

Fixing a Compression Faucet
Compression faucets are one of the most common types of faucets. Two-handled faucets are usually compression types...

Fixing Ceramic Disk Faucets

First, turn off the water supply at the shutoff valves. Then rotate the faucet spout to one side and raise the handle to expose the setscrew. Remove the setscrew and lift off the handle...

Fixing Ball-Type Faucets
Single-lever ball-type faucets are common on kitchen sinks. When repairing a ball-type faucet, buy an entire repair kit that includes O-rings, a new ball, valve seats and springs, and the special little cam tool you'll need to loosen the faucet cam...

Fixing Cartridge Faucets
Cartridge faucets often are the single-lever faucets you'll find on kitchen sinks. Leaks usually are caused by worn-out cartridges and old seals. On cartridge-type faucets...

Replacing Worn Valve Seats
When you close a compression faucet, the rubber stem washer presses against the inside of the valve to cut off the water. The place where the washer presses is called the valve seat...