Specifications: 

OEM cartridges have conductive grease on the PCR ends when new, but the grease typically wears out after one cycle.  Faroudja's conductive grease is applied to PCR end shafts to restore PCR conductivity.

By replacing the grease, drum charges improve and cartridge prints are darker and more even.  All that is necessary is to apply one or two drops of the conductive grease to the each side of the PCR (on the shaft end).