Label your child's toothbrush so there are no mix-ups. Soak toothbrushes in water with bleach. Once it has been soaked, rinse with water for at least a minute. Hang it upside down to air dry. One place you've probably never considered as a source of bacteria is your child's sippy cup. You figure it gets cleaned in the dishwasher, but that isn't always the case. Those valves, straws and other parts often become contaminated with bacteria and mold in hard to reach places. While some parents opt for disposable sippy cups to play it safe, that can be become costly in time. Invest in a small brush that can get those areas. Some parents swear by denture tablets. They simply dissolve the tablets in the water and clean the valves and other parts. Q-tips are also ideal as they can slip into those tough spaces. For an inexpensive fix, boil a pot of water and soak the cup and cup parts in the hot water.