On the market for more than 30 years; MOST POPULAR SHAVING AID TODAY. aerosol can is filled with a soap solution, the concentrate, together with liquid propellant added under pressure. The propellant, FORMERLY A MIXTURE OF CHLOROFLUOROCARBONS On shaking, some of the PROPELLANT becomes TEMPORARILY EMULSIFIED in the concentrate. On reaching atmospheric pressure the emulsified propellant expands to form an INSTANT FOAM