For clearing toilet drains, the best tool to start with is a toilet plunger, which has a flexible lip around the rim. Fill the toilet bowl with enough water to form a seal around the lip of the plunger when it's placed over the drain hole. Pump the plunger gently up and down until the clog clears. You should not have to use a lot of pressure. If the first attempt does not succeed, try pouring hot water into the toilet bowl and letting it sit for a few hours, then try the plunger again.