If a toilet is full and clogged, The Family Handyman recommends waiting about 10 minutes, if possible, to allow the water to drain naturally before using a plunger. After about half of the water drains away, it is possible to plunge as normal. Attempting to plunge the full bowl splashes water all over the bathroom.
It is possible to dip the excess water from the bowl using a disposable cup and bucket. Once the toilet is flushing again, owners are able to dispose of this liquid down the toilet.
Plungers with extension flanges work best on toilets. The bell of the plunger is full of air when first placed in the toilet. A gentle push forces the air out of it and allows it to fill with water with fewer splashes. Both the up and down strokes loosen and move the clog. Stubborn clogs require up to 15 or more repetitions to open the drain.
Keeping water in the bowl ensures the plunger stays sealed. Air in the plunger compresses and does not help release the clog. Adding hot tap water and dish-washing detergent helps break up the material clogging the drain. If the plunger does not open the drain, a closet auger is often helpful.