Deliverance Prayer to Cleanse a Location
Demons are in places according to the legal rights that have been established through humans by their sins at that location. To make the demons leave a place it is best to first cleanse through prayer, forgiveness, repentance or renunciation any sins you know of that have taken place there. Then when you command the demons to leave they will go as their legal rights have been removed.
It is also good to anoint with anointing oil (just a touch is all that is needed) anything in that place that the Lord might direct you to as you ask for his guidance. Anointing oil can be any kind of oil you have on hand, even cooking oil. If you say it is anointing oil, then that is what it is. Demons respond to symbol. At this point they should be getting very uncomfortable.
If possible put on a CD of Christian praise and worship music, or better yet, if others are there with you, they can be singing and worshiping as you are commanding the demons to leave. By now the demons should be utterly miserable and even scared.
In the name of Jesus, I command all demons to leave this place immediately. You have no legal rights to be here. We claim this territory for the Lord Jesus Christ according to the victory we have by his shed blood. (At this point you might begin to name the characteristics of demons you know would be there according to the evil you want to remove such as murder, destruction, fornication, etc.)
We command you to bow your knee to the Lord Jesus Christ because his Word says that, “At the name of Jesus every knee shall bow of those in heaven, those on earth, and those underneath the earth and every tongue shall confess that Jesus Christ is Lord to the glory of God the Father.” (Demons hate the Word. If the only verse you know is John 3:16, they hate that too. You don’t have to quote it exactly word for word; they’ll know what you mean and they cringe at the thought of it.)
The Lord Jesus Christ has given me authority to tread on serpents and scorpions and over all the power of the enemy and nothing can harm me. Now you must go, demons, because I have authority over you. (It is often helpful to personalize scripture by putting in first person pronouns.)
When you sense the demons are gone then ask the Holy Spirit to come and take up his abode in this area.