I did this on a Ford truck A/C years ago. Found a unit in a junk yard and put it in my truck. I can't remember the name of the stuff but I remember it came in areosol cans and I used two. After blowing it out with DRY shop air, installing new dryer and evaporator valve, it worked great. The unit had been sitting dormant for years. I was a little surprized that it even worked.