A mind-wipe is a system that Foaly invented to delete memories from an individual's mind. It is used by the LEP to keep the existence of the People hidden. For example, if a fairy was above ground and accidentally was seen by a human, the LEPrecon fairies would have to use a mind-wipe on the human to clear any memories the person might have had regarding the fairy.
There are two versions of the mind-wipe:
- The block or blanket mind-wipe, which deletes any and all of the memories in a certain time period. LEPrecon members could perform this type of mind-wipe with just the equipment in their bag. If a person has been mind-wiped, their mind will automatically fill in events to take the missing one's place. If a large portion of memories are deleted it can cause a drop in IQ.
- A fine-tune mind-wipe requires a team of techies and is supervised by Foaly himself. This type of wipe is used by Foaly and the techies looking at the individual's memories on a specialized screen which will "read" the mind's memories. This enables them then to delete specific memories only by either programming the equipment to delete memories on a certain subject or going in manually and deleting them one by one. The individual's brain will automatically fill in the gaps of memory with false ones, but the brain will not notice. This is so that the missing time in certain memories will not be missed. This doesn't risk as large a drop in IQ.
- In both types, the mind-wipe can be undone and the missing memories restored if the individual somehow sees an item, person, or place that evokes such strong emotions or flashes of the old memories that total recall occurs.
In The Eternity Code Artemis Fowl II and Butler experienced a fine-tune wipe due to their extensive knowledge of fairies and great time spent with them. However, Artemis (and Butler) managed to promote total recall by creating a disk of all their fairy knowledge and adventures before the mind-wipe and then disguising and entrusting the disk in Mulch Diggums's care.
When Opal Koboi is threatening the world a few months later, Holly Short finds Artemis to help. Of course, he has no idea of who she is, nor of the threat she is talking about. He believes his mind is making irrational scenarios in order to mask what is really happening. Though Holly hoped that seeing her would trigger recall, he only saw vague flashes of memories. Toward the latter half of the book, the human-fairy team runs into Mulch who produces the disk to Artemis. Artemis views the information on the disk and, after a few hours, his memories have returned. Earlier, Butler encounters Mulch as well. Even though it was difficult for the dwarf to convince Butler to view the information stored on the tiny disk, he eventually gave in and his memories returned after the video of Artemis appeared, saying Butler's real name, Domovoi (as Butler would only have revealed his first name under extreme circumstances).
On many separate occasions, mind-wipes have occurred to countless other people throughout the series. Note that if an individual is mesmerized not to remember anything (like during The Time Paradox when Artemis mesmerized his parents to believe that nothing had happened while he was away in Limbo), this is not a mind-wipe.