Kwikspell

Kwikspell is a correspondence course in Beginner's Magic. The course is designed to help adult wizards and witches brush up on their poor magic skills.

Harry Potter found a Kwikspell course advertisement on Filch's desk in his second year at Hogwarts. Some testamonials in the advert include "Madam Z Nettles of Topsham" (whose friends now bed for her "Scintillation Solution" recipe) and "Warlock D.J. Prod of Didsbury" (who is now able to turn his wife into a yak for making fun of his poor magic skills).