Next time you check into a hotel room, this must be the first thing you check before touching or using anything in the room.
What are we talking about.... the plug in the bathroom sink. Why ?
If the bathroom plug looks like the image below, do not touch anything else in the room, especially the mugs.

You will see a ring of dirt around the plughole... here's a close up...

Here's the issue. The ring of dirt evidences two key issues:
1. The sink has not been cleaned for a very long time
2. Housekeeping use the bathroom sink to wash the mugs and glasses in the room. This is achieved by using a specialist solution in the sink with hot water that removes any stains on the crockery and sterilises. If the housekeepers had correctly cleaned and sterilised the crockery in the sink, with the correct solution, it is impossible that this ring of dirt would ever exist. In fact, if the above process is completed daily, the sink, plug hole and surrounding area would be spotlessly clean.
The dirt around the plug hole is easily removed with a tissue or swab and requires no chemicals, so why is it that so many sinks have this ring.
The answer is simple:
We have evidenced this hundreds and hundreds of times yet hotels are failing guests by allowing their housekeepers to go unchecked and not provide a clean and hygienic environment .
For a Guest that uses the crockery or glasses in the room, it is likely that they will contaminated with bacteria and could make you ill.
Our advice, try changing rooms to one that has a clean plug hole (although after four room changes at a London Heathrow Hotel, the hotel management couldn't provide a clean room - see more here) or boil a couple of kettles of water and fill the sink with boiling water with the crockery in the sink (not the glasses to avoid them cracking). Allow to soak to 5 minutes, remove and use.
Hotel operators, get in contact for a full review of your housekeeping protocols and adherence to cleaning protocols.