Reconditioning Brake Lines
For the inside, how long have they been open to the atmosphere?
Were they stored in a dry or damp environment?
If you could feed a cord through (piano wire might be stiff and flexible enough to do the longest runs) you might be able to pull a pig through the tube. Like a pipe cleaner.
Just be sure you can get it out if the pull cord breaks.
Also be carefully about removing any coatings on the inside or outside of the tubing or you will start a spot for rust to take hold.