“By returning six [6] M·A·C primary packaging containers to a M·A·C counter or M·A·C Cosmetics online, you’ll receive a free M·A·C lipstick of your choice as our thanks to you.”

Humans of the world, were you aware of this? I've been taking advantage of this program for years and don't have any plans to stop. You can find more information on what can be recycled here.