Thanks Toni for getting back with answers to my post. Also I sleep in a bite guard (one of the hybrid ones). When I take it out in the morning I use a toothbrush and scrub it with Peroxil, rinse and put Peroxil in the cupped side before putting it in the case till evening. I figure that the hydrogen peroxide ingredient should kill bacteria. I know I could just use hydrogen peroxide but I do a mouth rinse at the same time so it's convenient. Comments anyone.