With help from University of Arizona microbiologist Charles Gerba, Andrew Weil put together a list in his January Self-Healing newsletter of the nastiest germ sources at home and elsewhere.

¢ Kitchen sponge vs. toilet: There’s more contamination in the kitchen sink, so change or sterilize the sponge that wipes it frequently. (You can sterilize it in the dishwasher, or heat it, wet, in a microwave oven for one minute.)

¢ First-floor elevator button vs. ATM keypad: It’s a tie for germiness. Wash your hands after using these buttons, or do as Dr. Weil does: Carry alcohol-based hand sanitizer.

¢ Bedspread vs. TV remote in a hotel room: TV remote, because it’s often the first thing people touch. Again, wash your hands after using, or use sanitizer.

¢ Grocery-cart handle vs. drinking fountain: One of Gerba’s studies found that 55 percent of handles on grocery carts were contaminated with bodily fluids (such as urine and saliva), and 21 percent showed traces of blood. As for public fountains, the ones at schools rank germiest.

¢ Kitchen-sink drain vs. shower drain: The kitchen sink’s worse. If yours smells vaguely of rotten eggs, pour 1/4 cup of baking soda followed by 1/2 cup of vinegar down the drain, then flush with hot water.

¢ First vs. middle stalls in restrooms: “Go for the first stalls because fewer people use them,” Gerba said. Afterward, wash your hands as if you were Lady MacBeth.