While you're applying mascara, it's easy to smudge some on your eyelids, which is a pain to clean it up. YouTube user Michelle Phan reused old business cards to make eyelid shields, which also grab on to all your eyelashes easily.
You can use any old business card for this. Place the card above your eye and, while looking in a mirror, mark where your eye starts and ends. Also draw the general curve of your eye from one end to the other. Grab a pair of scissors and cut this part. That's all you need to do.
Put this new business card shield to your eye and lift up. It will protect your eyelids from accidentally being smudged while applying mascara -- and it can be used on both eyes as well as above and below. Phan notes that it also makes it easy to grab every single eyelash.