Most of the time, wax never builds up to a degree that causes a hearing loss because it is shed a little at a time out of our ears. Built-up ear wax can block the doctor's view of the ear drum and make an accurate diagnosis of an ear infection impossible. By the way, ear wax can be either brown, blackish, or yellow. This move generally pushes some or all of the wax further in, rather than effectively removing it. Worse, this habit places the terribly delicate canal skin at major risk of injury.
Commercial ear drops containing glycerin and other chemicals do work.
Do not use them if you know that you or your child has a tube or a perforation, do not use them if you are not sure. Better to see an ear specialist for wax removal done with the trained doctor looking at the ear and using specialized equipment. These are generally prescription.