Wanted to add that for anyone who would like to test this method without a bigger investment, the dollar stores often have small packages of the foam ear plugs. They are not a bargain price compared to the larger quantities, but you'd only be out a dollar if you decide you didn't like it.
I was just remembering a time when my daughter was visiting and we had a guest bed in the sewing room (no, not a sewing machine in the guest room, though we had that, too!). She is extremely sensitive to sounds, so things like our clock chiming in the night would wake her. When she saw the big jar of ear plugs on the sewing table, she assumed I was being considerate of her and she used a pair. They do work for their original purpose, too.
