Kärcher Soap RM21 – To wash the hair and body, RM21 is rubbed to make a foam and applied to damp skin and/or hair, and then rinsed off thoroughly after a brief time. Alternatively, RM 21 can be applied to the skin as an aqueous solution or foam with a concentration of 0.5 to 2 % using an automatic dosing system. RM 21 is available in 30-litre canisters or 500-ml bottles. When stored in closed containers, the product has a shelf life of four years after production. It is biodegradable, dermatologically tested and conforms to Cosmetics Directive DIN EN ISO 222716..