Locate the type of sink stopper (lift-and-turn, lift rod, push/pull, pop-up/flip-it, or removable strainer)
Lift-and-turn: Turn the stopper counterclockwise, then lift it out
Lift-and-turn (stuck): Soak around the rim with penetrating oil, wait, then try turning counterclockwise again
Lift rod (with tailpiece): Remove the pivot rod clip/retainer under the sink, then disconnect the rod from the stopper
Lift rod (with tailpiece): Unscrew the retaining nut/locknut holding the stopper assembly, then pull the stopper out
Push/pull: Push down to release, then pull up; if it won’t release, wiggle while pulling up
Pop-up/flip-it: Lift the top cover/stopper slightly, then pull straight up to remove the assembly
Pop-up/flip-it (disassembly): Unhook the linkage (if present) under the sink, then remove the retaining nut/assembly
Removable strainer-style: Unscrew the strainer/stopper from the drain assembly, then lift it out
If a rubber plug is present: Pull it out by hand; if tight, use needle-nose pliers to grip the edge carefully
If you can’t access hardware: Remove the P-trap or open the cabinet for better access
After removal: Clean the threads/seal surfaces, then reassemble with fresh plumber’s grease or a new gasket if needed