Catherine Devine, Allure magazine
I'm really close with my sister. We're two years apart, and we've shared just about everything-clothes, friends, and even a bedroom when we were little. I consider myself a pretty decent sharer, but when it comes to my makeup, I'm not as easygoing. I'm cool if she wants to borrow my bronzer every now and then, but the second she reaches for a mascara, things get serious. It's not a competitive, sibling-rivalry thing, like, "Ugh, this mascara will make her lashes longer and thicker than mine, so she absolutely can't use it." It's a germs thing-no matter how close we are. I wouldn't share my mascara with anyone. (Why, hello there, pinkeye, it's so nice to see you.) People gross me out.
See more: The 10 Commandments of Mascara
We recently asked our Facebook fans if they considered themselves beauty-product germaphobes, or if they were open to sharing, and more than half admitted that their makeup bags are completely off limits. Interestingly, 31 percent-a group I guess I'm part of-admitted they sometimes share, but many cited only with family and close friends. I thought that was kind of funny-aren't those pretty much the only people who are a) likely to be in such close proximity to your makeup bag and b) comfortable enough to ask?
The point is, it's not necessarily who you are sharing with, it's what you're sharing and how you're doing it. These are the tips we stand by when testing makeup at beauty counters-hey, if they work at a public makeup counter, they work for one-on-one sharing:
See more: Top 21 Drugstore Beauty Bargains
Eyeliner and lip liner: Sharpen all pencils before using with a clean sharpener. This cuts out all the contamination that lives on the surface.
Concealer stick and lipstick: In the store, we'd recommend dipping the entire stick in alcohol, but since that may be awkward to do in front of a friend, wipe off the top layer with a tissue and apply with a cotton swab.
See more: The 6 Most Flattering Haircuts for Round Faces
Powder blush and bronzer: Again, if your friend is cool with spritzing alcohol over her powder, go for it. Then, scratch off the top layer so you're not applying wet powder. And make sure you're using clean brushes-Sephora Makeup Brush Cleasing Wipes make things pretty simple.
Foundation: If it's a pump or tube, it's safe to use. Just wipe the opening with an alcohol pad first.
Anything that comes in a pot: Don't do it. Seriously! Dipping a finger in will contaminate the entire jar, and using a Q-tip won't be any better: Your friends' germs are already all over the place.
See more from Allure:
The 12 Best Eye Creams
10 Hairstyles That Make You Look 10 Years Younger
Best of Beauty 2012
The 10 Most Gorgeous Hair-Color Ideas for Brunettes