Clarification note before you start reading:
Spirit-angels and spirit-demons are in referral to unresting souls, haunters or angels who permanently reside on earth, via a grave they reside in nearby. Angels or demons living in their respective domains are unaffected (as their homes are of different existential planes). What still DOES apply is possession between both kinds, those still work on them, as the spirits are possessing mind/body, not their own physical bodies.
SPIRIT ANGELS
In order to get rid of a spirit (NOT by exorcists, priests or magic), the following laundry-list has to be done;
- Find their grave
- Take away mourning-items such as bouquets or candles from any location
- Rid of all memorials/photos related to the spirit
- Dig out their remains
- Destroy the remains by burning them to ashes
- Do NOT spread ashes somewhere- discard into some random trash bag and make sure it lands in a trashyard or garbage burning factory.
And done. You've gotten rid of a real person, by forcefully making them unexist you monster, just for them haunting or trying to kill you, if that was their reason to stay a spirit and haunt you in the first place.
The main reason why, is that their resting place had been destroyed (no regeneration) and disrespected, by not having a proper, permanent resting place. Angels regenerate faster with beloved items or flowers near their grave..So to completely take it away, means it drains them completely of their being. Destroying the body, where their spirit originated from, will assure, they will not be able to reappear anymore.
Thus, destroying their grave and body will forcefully make them stop their abilities to regenerate and have a "spawnpoint" for the earth down below.
The next step, to rid of angels, would be to get a demon to infect them, it causes them to lose all of their "self" and become a completely different person.
SPIRIT DEMONS
For demons, you can only get rid of them, if the demon is willing to listen to you. The only way to get rid of them without force, is to talk to them.
Simply asking them what their life was like, if something was on their mind or other questions, that can appease all the negative emotions they kept inside for years, will gradually calm their upset spirit and be freed from earth, returning to the Dystopian Core.