Ahh, the good ‘ol days of flushing out the reefer pipes (R-12 system) with 15 or 20 gallons of R-11 pushed thru by 100 or so pounds of liquid R-12 to clean all the burnt compressor crap out of the system so you could get the freezer back online before the Captains ice cream melted.
I slaughtered my some Ozone molecules that day !!
Never really believed that bit about destroying the ozone as it is my understanding that R-12 is heavier than air;goes into the ground eventually.