We've all been there: You have friends over for dinner, you notice your dining companion about to dig in, and, for whatever reason, you also know they haven't washed their hands. Powerless, you look on in horror as their hand reaches, as if in slo-mo, arching through the air, ultimately making contact with a pita chip. Which is then dragged through the delightful pesto you made with the last of your summer basil, dripping germs and who knows what else.

And now? Now that pesto is ruined, at least for you. You consider ending the friendship, but in the grand scheme of things, not washing hands isn't quite offensive enough to warrant that. Well, I guess it really could be, depending on what was on those hands. But it's unlikely.

So, what to do instead?

In the Social Qs column in the New York Times earlier this month, Philip Galanes answered a letter from a writer who had a guest who forgot (or deemed unnecessary) that crucial step. The scenario involves playing chess, not sitting down to dinner, but his advice holds, I think. (As an aside, if you don't already, please read his column. The man is a brilliant arbiter of modern etiquette and kindness.)

"Try to keep quiet about other people's hygiene. We are all filthy beasts," Galanes writes. If that doesn't work? "If silence will inhibit chess dates, try: 'Let's respect the new board and wash our hands before we play.' He may think you're weird, but as long as you both do it, you save him the indignity of knowing that you've been monitoring his bathroom habits."

Here are a few more ways you can suggest to keep your grossest friend from poisoning everyone's food — without shaming them.

5 Ways to Get Your Guests to Wash Their Hands

1. Use your kids to your advantage.

Got kids? Remind them fairly loudly but in a pleasant, matter-of-fact tone to wash up before dinner. "Jack, can you set the table, please? Don't forget to wash your hands first."

2. Wash your own hands.

Send a subliminal message by washing your own hands. Feel free to make it a bit of a production. I usually wash my hands in the kitchen before I start cooking and, while my friends seem to be hand-washers, a brief, faux-casual but dramatic demo might do the trick if they aren't.

3. Ask them to check the soap.

When your guest is headed to the bathroom say something like, "Oh, dear. I'm not sure I replaced the hand soap in there and we were running low. You'll let me know if you need some?"

4. Say it in another language.

My friend from Italy (Ciao, Mariah!) brought me a little Italian dish the last time she visited South Carolina. It reads prima ci si lave le mani or "First wash your hands." Indeed! Guests will almost always ask what it means, but they won't be offended because it's in another language, which makes it cute. But it will also make them wash their hands.

5. Be direct.

"I feel like we've had quite a time with every virus and bug this year! Would you mind washing your hands again, just in case? I'm doing everything I can not to take another sick day." Then immediately change the subject. If you have to say something awkward, be clear, say it quickly, and then pretend it never happened.

Have you had this problem before? What's worked for you?