I'd like to start with I think the subject line should be allow you to put another word in the subject because I was going to say "vanish?" I've been an active witch for a long time in my option ( Currently it's been 17 years) I think I'd like to say this in case any new witches or people who just want some information.
Cleanse = Cleanse means to remove energy this works by basically "dislodging" the energy from the target being cleansed. Think of it like if you spill crumbs on the floor. By sweeping them into a dust pan you have "dislodged" them however they still exist in the space.
Banish = Using our example from above say we put those crumbs into the garbage and took the bag out, and put it in the outside bin. We have banished the crumbs. Now in magick banishing is when you drive something away from your space, you kick them [the energy or the spirit] out and thus ridding them from your space. However make sure protections are recast to keep them from coming back and don't forgot how useful wards can be.
Purge = This will "reset" the energy of something, if I was to take a crystal and purge it I am therefor resetting this crystal back to when it was first formed in the earth, it now has not even a single thing left in it. So if I was to want to program this crystal for my own needs if I was to get it from a shop or another witch , etc I would purge it so I can make use of it in the form it was created as.
Now my question is can we "vanish" energy? The right word I'm thinking of is like transmuting but does that get rid of the energy? I believe it just "converts" it by changing the polarity (like negative to positive] I've never once thought about just seeing if we can "wipe the energy from existence" spiritually I mean not physically obviously. Please let me know if that makes sense , don't want to confuse anyone.