The PVA coatings, which are normally dosed with anti-fungals, are intedned to keep a rind clean and spotless (uncontaminated) in the few weeks before waxing. It is used on swiss and gouda types normally, but can be used on any rind you want kept clean. Note that it is only effective for 4 weeks or less. If you want to use it longer it needs to be reapplied as the antibiotics in it degrade.