I may be big and ugly, but I'm not the black death.
The "black death" is a condition that occurs in primarily Nippondenso compressors (this especially includes the one's Ford builds under license). It is prevalent in these compressors because they use teflon coated pistons instead of piston rings. What makes the black death is not the black of the powdered aluminum in the mix. The death comes from the special characteristic that vaporized teflon adds to the slury of melted, gauled, aluminum, oil and refrigerant. The teflon bonds the stuff together in a solid at room temp. The stuff coats the whole system with something thats a little darker and very much like graphite. The big problem is the stuff in the condenser. When the system is flushed and repaired the condenser get hot during operation and the stuff goes liquid and gets back in motion.
Its about impossible to flush but I would not even consider flushing the condenser in such cases, just pitch it.
Bosch Master, ASE Master, L1
33 years MB technician