News, views and top stories in your inbox. Don't miss our must-read newsletter Sign up Thank you for subscribing We have more newsletters Show me See our privacy notice Invalid Email

Along with a copy of the Bible, those theft-proof hangers and sachets of instant coffee, the other hotel room-constant are the glasses you get in the bathroom.

Nearly always in pairs and often placed upside down on a paper doily, they're handy for popping your toothbrush in, or to have by the bed.

Outside of that, you probably don't give them a lot of thought.

If that is the case, you might want to start insisting on being brought a different glass, or bringing your own drinking receptacle.

The reason being, there's every chance the glasses you find in your hotel bathroom are not nearly as clean as you expect them to be.

Dirty glasses

An undercover ABC News investigation uncovered some unappetising information. They looked into cleanliness at 15 hotels and found that staff in 11 of them did not wash the glasses thoroughly - nor did they replace them with fresh ones, as reported by The Sun .

(Image: Rex)

Instead, they were simply rinsed off and put back where they were.

Aside from not being able to account for how hygienic the previous occupant of the room was, there's the fact that these glasses are often in the bathroom, with their potential riot of germs.

Perhaps this was an isolated incident and the people in this area simply aren't keen on cleaning glasses - or just a coincidence - but it'll certainly make hotel guests think twice about filling up.

What goes on behind the scenes in hotels is a constant source of fascination - although it's not always reassuring to hear.

In an article published on Mirror Online yesterday, several hotel workers anonymously confessed to some grubby secrets .

(Image: Getty)

These included picking off a plate of room service food before being presented to the guest. Washing blankets didn't seem like it was a priority either.

But it wasn't all bad news. Hotel workers also admitted to acts of kindness and spontaneous upgrades to people they felt deserved it.

Just bear this fact about glasses in mind, and if you ask for fresh ones, ask nicely.