12 Common Beauty Questions, Answered

9. Is it OK to store sunscreen or a lip balm with SPF in a glove compartment?

No, especially during summer. Once the car heats up in the sun, "high temperatures can cause the sunscreen’s active ingredients to degrade right in the container," says Badreshia-Bansal. And the lip balm will melt, to boot. "When you apply a degraded sunscreen or balm to your skin, you’re not getting the SPF that’s indicated on the bottle," she warns. "In fact, you might be applying nothing more than a thick moisturizer."