Reconditioning Brake Lines

Yes, just replace them. If you never want to worry about your master leaking and destroying your paint, go with DOT 5 brake fluid, it doesn't attract moisture either.
I run the same stuff in the Harley it's silicone based... it works great especially down here in Florida where it's high humidity even though that's a seal brake system somehow they still attract moisture especially if you don't run the things everyday. At one point I had a tool belt around my shoulder like a bandolier a skill saw and Sawzall w/ a 12" blade sticking outta my saddle bags....riding to framing jobs EVERY DAY.... I got some crazy looks, Brother...