Since this thread opened again, will add in: (dont think I put this in last year)
3 years ago, 'just for kicks' I built up an evaporator for a water source HP from used Cu pipe that had been open to the air for years, and used an old carrier finned tube HE out of the scrap pile for the condensor - which had also been open to the air for over 10 years.
Incentive was the high price of copper.
Filled the pipes and HE with a 10% solution of ferric chloride and let sit for 3 days, insides of pipe nice and shiny, with loose black Copper chloride suspended in the solution. Hooked up water hose to the setup and flushed for a few hours with well water.
Pulled vacuum, let it run for a few days till <300 mirons held indication all water evaporated.
Installed in system with all N2 precautions on silphos brazing, etc.. Has been running fine for 3 years, no problems.
Lotta wait time involved, but little active time, not something you would want to have to travel to a job for on a customers old lines - and if you did, undoubtedly the vac pump would 'walk away' overnight? Probably not worth the time except to having seen if the proceedure works - have done similar for over 40 years with no failures I could track to the cleaning process. Have Never tried it on anything except pipe and tubing, pretty sure the technique would destroy a txv or compressor.
BTW, have never put anything except refrigerent and the correct oil in any compressor.