Infestation of a house
Infestation is a phenomenon by which the devil possesses a place. Infestation of a house can take place when spiritism, satanic rites, Santeria (voodoo) or other forms of esoteric activities have been practiced continuously in that house.
When the devil possesses a place, he can move things at will or provoke noises or odors. These are the famous cases known as poltergeist. These phenomena are not produced by unknown spirits, but rather by demons. This can be proven by the fact that with prayer all cases of poltergeist disappear.
We must tranquilize the inhabitants of these places, telling them that an infestation never provokes the possession of any of the persons living there.
In these cases the priest can pray once in the house and then encourage the family to join daily to pray together. They can pray the rosary, read the Bible jointly, sprinkle holy water in the rooms, join before a sacred image and pray for protection, etc.And of course to ask Santn Michal to expel that bad spirit..
In the cases of infestation, the families usually ask the priest to do everything. However, the priest must make the people understand that they themselves can do what they ask the priest to do. The united prayer of a family can perfectly break the power of the devil over that place if they persevere praying together during weeks or months. If after this period, the phenomena persist, then they should recur to the priest.
Appendix for priests
The priest should not easily believe the testimonies about the things that happen in a house, unless there are testimonies which have at least two witnesses. When a possessed person comes to see a priest, the priest can pray and verify the manifestation of the devil, but in the case of infestation, nothing happens when the priest prays in the infested place. So he has to depend completely on what he is told. As a result there is no way to reach a certainty about whether there is in fact an infestation or whether it is all the fruit of autosuggestion. The only way to acquire certainty is that different witnesses coincide concerning the extraordinary facts that have been referred.
Only in those cases in which the phenomena are very serious and the family has been praying for weeks, the priest could ask for permission from his bishop to go to the house and use the rite which appears in the Appendix II of the Rite for Exorcism
In general, almost all cases are due to autosuggestion. But by saying almost all is not the same as saying all. If not, the Church would not have included its Appendix II.