Condenser line fittings corroded together. Suggestions?

Condenser is staying in the car, but I want to remove the line.The top line is broken free and the nut spins freely on the line, BUT the line is still as tight as can be into the fitting.Does penetrating oil or heat work, or are these things that should be avoided? I don't want to start prying and screw up the threads or flared end. Thanks in advance, Kevin.

 

I would not heat aluminum.You will more likely then not replace the part in question.

 

Tapping with a small hammer got the parts to loosen up enough.Thanks.