With a lot of older R22 units, you can "pump them down" where the compressor actually accumulates all the R22 and pulls a near vacuum. Then, if you disconnect i

With a lot of older R22 units, you can "pump them down" where the compressor actually accumulates all the R22 and pulls a near vacuum. Then, if you disconnect it from the coolant lines you can bring the whole unit to a reclamation center. Even my old unit was able to pull a 1200 micron vacuum on the lines. Unfortunately, my r410a units regularly vent to the atmosphere because flare fittings suck.