One of my all-time fave beauty tools is Q-tips! There's the regular round tip ones that I grew up with that I use to help smudge my eyeliner for a smoky look.
There's also the Precision Tips that I have found incredibly useful for helping my DIY manicures- dip the tip in nail polish remover to clean the edges. I also use this when applying red lipstick or any color that needs complete precision. It's so easy for the extra lip color to smudge outside your lips, so it's helpful to fix those boo-boos.
If you're on the go, they also offer Q-tips in a handy-dandy travel case! No need to put them in ziplock baggies or even loosely in your cosmetics bag. It helps to prevent germs as well as ensure you have enough of a supply for each time you use them!