One of the prerequisites of home ownership is some basic knowledge about plumbing. By learning a few tricks about how the different processes of plumbing work, frustrations can be alleviated. If a sink in your home is draining too slowly, removing and cleaning the stopper can often fix the problem. And there's no need to call a plumber to get the job done.
Remove items out from under the sink before starting this project. Lie on your back with your head toward the back of the sink cabinet.
Place the flashlight in a corner of the cabinet, facing the bottom side of the sink so you can see what you are doing. Locate the plunger rod coming down from the back of the faucet.
Locate the clip that the plunger rod slips through to hold another rod that leads to the sink stopper. This rod enters the drainpipe directly under the sink drain and before the "P" trap.
Locate the nut on the sidewall of the drainpipe. Reach up with your hand to see if you can remove it by hand. If it doesn't turn, use pliers to remove the nut. Then go back to the clip and squeeze the ends together. This will allow you to push the plunger rod out. This will free up the rod leading to the sink stopper.
Remove the rod from the sink stopper and set it aside. Climb out from under the cabinet, remove the sink stopper and clean it. To replace the stopper, follow the previous steps in reverse order.