Originally Posted by
stealthnc
I've heard of filling up the tub with water and hanging wet towels out in the room.
It works better if you fill the tub with the hottest water you can get and let it really steam up, and leave the bathroom door open.
Be careful not to set off the smoke alarm with the steam though - usually, hotel rooms prone to this problem will have a sign on the bathroom door asking you to close it when bathing/showering. In which case, you might have to sit in the bathroom with the door closed
Actually, some hotels have a humidifier. It may be worth asking if they have one.