If you suspect a toilet is clogged, don’t flush or it might overflow.
To unclog the toilet, first dump out or add water so that the bowl is half full. Then use a funnel-cup plunger, this is specifically designed to fit the bowl’s trap. If the plunger does not clear the clog, use a closet auger. The closet augers curved tip reaches more deep-set clogs and its protective cover won’t scratch the bowl.
Closet Auger: Use a closet auger to break up a deep-set clog in the toilet trap. Maneuver the auger while simultaneously pushing it and turning the handle to push out the clogged trap.
Preventing an Overflow: If a toilet is about to overflow, swiftly reach into the tank; push the tank stopper down into the valve seat and hold it as you turn off the water valve.