Consider yourself warned!

If you find yourself among the roughly 3 million people who are traveling this time of year, filth and germs could be hiding in plane sight.

Flight attendants recently opened up to Travel + Leisure about the five dirtiest places on an airplane so that passengers can arm themselves with knowledge — and some hand sanitizer.

The overhead bin

What goes up must get dirty, according to flight attendant and travel blogger Josephine Remo.  She said that overhead bins are “rarely cleaned” and “touched by a lot of people.”

She recommended that people use a cloth or wipe the surface of the overhead compartment before opening it and that they also clean their hands afterwards.

Safety instructions

Perhaps the safety instruction card should add a bit about hygiene after reading it.  “The dirtiest spot on a plane is the safety instruction card in the seat pocket,” Remo said. Not only can passengers wipe down the cards and sanitize their hands before reading them, but they can also pay it forward by wiping the card before putting it away.

Tray tables

The tray table is frequently used on airplanes for eating, and as one disgusted flight attendant explained, some parents dare to change their children’s diapers on top of the tray table. Tray tables do get a wipe down, but it couldn’t hurt to clean one for yourself before eating off of it or resting your head on it for a nap. “Passengers generally know airplanes are riddled with [grime], but the [tray tables] go beyond general germs,” flight attendant Sue Fogwell told Travel + Leisure.

Seat covers

Every passenger on the plane must sit for several hours at a time. Even though people might get airsick or vomit on board or even have an accident, seat covers don’t always get sanitized.  “The seat covers aren’t always replaced or cleaned,” Fogwell said. “Not every gross event is reported, [as] it could create a flight delay,” she added. If people want to sit out of resting on a dirty seat, some retailers sell reusable and disposable seat covers.

Bathroom doors

Not surprisingly, the bathroom is a hotbed of bacteria, and while the insides of the airplane lavatories are cleaned, the door handles are sanitized less often.  “The toilets are regularly cleaned, but the locks and door handles are not,” Remo said.