Today I managed to buy a 1979 Motobecane Super Mirage in great shape.

When I got it home I tried to adjust the seatpost, and found it had frozen. After a fair deal of coaxing and pulling I managed to pull the post out enough, but not before creating a nasty scratch. I think it may be a burr inside the tubing, but I am not sure. The aluminum post has a scratch that seems it may be too deep just to "buff out". Is there a good method to fix this problem, or prevent it from happening again? Also, is there a good source of accurate Super Mirage seatposts that will fit my bike?

Thanks,
Jake