Thu Aug 23, 2012 8:37 pm by 37ULH
Cleaning the ends of the manifold hasn't a lot of bearing as there is no seal effected there. Perhaps he meant the ends of the nipples which can be flattened and minor nicks removed by using using self stick sandpaper on a piece of flat glass.
If the manifold has any defects, has been previously machined or is out of round there are techs out there that can remachine it and make custom fit peek seals. If your manifold is perfect then Enfield Racing can provide a peek replacement for the seals that allows for easier sealing with less risk of loosening the inlet nipples in your cylinders.