Crab Apple is known as the cleansing remedy, and as such is the added 'sixth ingredient' in Rescue Cream. Its main use is to help people who feel that they have something unclean or poisonous about them, or who dislike some aspect of their appearance or personality.

Sometimes there might be very real things wrong with someone in this state, but they will disregard the big problems and concentrate obsessively on the one thing that they have fixed on. This is why Crab Apple is sometimes given to people to cleanse obsessive, repetitive behaviour such as hand-washing, re-checking that appliances are unplugged, and so on..