My brother once told me that there were ghosts wonder around in school, play ground, hotel or any building that was empty at night. They believed that the spirit shall take over the places where human 'chi' was less.
As for hotel, we need to knock at the door before we enter, upon opening the door, we need to step aside, let that 'someone' walk out from the room first, this is the respect to them, later, we turn on all the lights, wide open the window and let the fresh air and sun shine in. Guarantee best night sleep.
Some believe that baby and toddler have the tendency or third eye of seeing the spirit, if you wish to buy new house, bring them along, if they are happily playing inside the house, then house is 'clean', if the baby is crying, you better on hold the house buying.
After memorial or funeral service, good to stop by temple and pray, but if you are non believer, alternatively drop by public places like supermarket, hypermarket where the 'yang' chi are rife and deter spirit from following you home.
If you do have eerie or spooky feeling at home, cleanse by sprinkle salt at every corner of your house, leave it overnight and sweep away in the next morning.
Believe it or not? It's up to you, if you know more, welcome to share with us.