Good question . . . I have a 1970 Sport Satellite with factory a/c and just used a wire brush to make it look clean. As I understand you can get a kit with the seal, if yours is leaking. Apparently it is like $20 and easy to do, rather than sending to someone and spending $150 to have them do it.

But, check with classic auto air in Florida, they say they restore hoses, etc . . .

Mark