I am really surprised that no one has noted Boeshield T-9. This stuff is amazing. I will say that I was always a die hard linseed or JP Weigle guy for all my frames. Now I found Boeshield and will never use anything else. It was developed by Boeing for use on their air craft parts that they did not want to get corroded. It sprays on like WD-40, makes very little mess when it comes out of the tubes (unlike boeshield and linseed which can be a pretty sticky mess) and then it dries to make a nice thin film on the parts.
I actually use it as well on the tops of my bandsaw, table saw, etc to keep them from getting surface rust. Application is the same as the other products, spray in and roll the frame around to coat the tubes inside.
I highly recommend checking it out.....