I'm a real dummy on this issue so I've got to ask you to help me understand the purpose of the nitrogen. I understand using it to displace air, but how does it flush actual debris like compressor seal residue and sludgy oil out of the system? I've seen pictures of orfice tubes that are blocked with crud and vendors selling solvents for flushing and auto A/C guy swearing up and down that you've got to physically flush out debris <img src="/forums/images/graemlins/scared.gif" alt="" /> Does nitrogen do all that? Thanks for bearing with my ignorance. -- Matt