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This way, you'll be prepared for the process. To disassemble your faucet, you'll need the following:  A pair of pliers An adjustable wrench A phillips or flathead screwdriver You do not want water pumping into the faucet while you're disassembling it. Under your sink, you should see a couple of valves just behind the pipe.  Switch these valves to the off position. Turn the valves clockwise to do so. This will prevent water flow while you work. Turn the hot and cold faucets on to drain the water between the spigot and the shutoff valve. These are the small caps on top of the faucet. They may read "hot" or "cold." You can remove them by simply inserting a flathead screwdriver just underneath the caps. Gently pry the cap off. It should come off without too much effort. It's a good idea to wrap the screwdriver cap in a cloth prior to removing the cap. This will prevent you from chipping or denting your faucet. Some faucets have a small standard screw just underneath the cap, while others have small allen head screws recessed into the handle. This is attached to the washer. You must loosen it to remove the handle of your faucet. Use your Phillips head screwdriver to remove a standard screw, or an allen wrench to remove an allen head screw.  Once the screw is removed, gently wiggle the faucet's handle back and forth. Eventually, it should come loose. You can then pull out the handle. Not all faucets have a handle. If yours does not, you can skip this step. However, you should still remove your washer's screw. The stem, sometimes called the bonnet, is a small circular piece that sits above the washer's valve that looks something like a donut. Gently clamp your pliers around the bonnet and pull it out of place. You may need to wiggle it back and forth to get it loose.  If the stem seems to be stuck, spray it with WD-40, wait 5 minutes, and try again. Some stems cannot be pulled out with pliers. If you can easily twist the stem, this means you will need to twist it off instead. Make sure to place the stem in a safe place. You will need it later when inserting the new washer. Use pliers to take out the old cartridge. Make sure there are no pieces of rubber or parts of the stem or cartridge left behind. You now have access to the cylinder-shaped washer contained inside your faucet. Using your pliers, pull the washer out of place.  There are circular rings, called o-rings, that suction the washer to the faucet. You will have to grip your pliers tight and pull with a little force to remove the washer. Note that on some faucets, the rings and seals are built into the cartridge. Worn out o-rings can cause a faucet to leak as easily as a worn washer can. If the leak is coming from the base of the faucet, the o-rings are probably worn. Place a pair of replacement o-rings at the bottom of the faucet before inserting a new washer.

Summary:
Gather your tools. Switch off the water supply. Remove decorative parts of the faucet. Take off the faucet's handle. Remove the stem with pliers. Take out the old cartridge with and the washer. Determine if you need to replace the o-rings.