Spending a night in a hotel room can be relaxing. But even if it feels homey, your room likely still contains plenty of invisible germs. So, what can you do? According to health inspectors, microbiologists, and various other experts, you can start by avoiding — or cleaning — a few certain items.

Hotels may provide you with drinking glasses, but in some places, you might be better off drinking from the faucet.

One undercover investigation into the cleanliness of hotel rooms conducted by ABC15 revealed that hotel room drinking glasses can be so dirty they pose a potential health hazard.

Out of the four hotels examined in the investigation, three failed for nauseating reasons ranging from hotel staff using a towel or sponge to wipe them "clean" or not even replacing them with fresh ones for the next guest.

Other ABC News stations conducted their own investigations and found similar results across the United States. One housekeeper at a hotel in Cincinnati, Ohio was seen spraying dirty drinking glasses with what appeared to be Lysol mildew remover.

At another hotel in Cincinnati, investigators witnessed a housekeeper drying drinking glasses with a dirty hand towel. Housekeepers at a hotel in Phoenix, Arizona were also observed rinsing and drying dirty drinking glasses with a rag.

Watch the video to learn what you should never touch when you stay in a hotel room!

#Hotels #HotelHacks

Drinking glasses | 0:00

Coffee machines | 1:15

Bedspreads | 2:15

Pillowcases | 3:35

The bathroom counter | 4:30

Remotes out of control | 5:28

Lamp switches | 6:32

Stay off the phone | 7:24

Don't touch the desk | 8:10

The ice bucket — and the ice | 8:43

Carpets | 9:51

What can you touch? | 10:34