Do you want to prevent soap scum and hard water deposits from marking up your glass shower doors? There are chemical sprays that can create a siliconelike surface on them, which makes water bead and helps the doors dry more quickly. But you can also use an item from your pantry to get the same results: a potato. Simply cut a potato in half and rub it all over the inside of your shower door. The natural starch from the potato will act like an invisible barrier and help keep your shower doors clean.