[header] How to clean a sink trap [title] Remove any sink stoppers. [step] If your stopper has a pivot rod, then you will need to remove this to remove the stopper. Look under the sink and locate a locking nut where the pivot rod goes into the drainpipe. 
Unscrew the nut, pull out the rod, and remove the stopper. Then screw the nut and rod back in place without the stopper.