Max, it takes a good polisher about 120 hours to polish a KATANA blade, and to be able to do this without taking too much material off the surface and without changing the very special shape of the blade, he has to pass a very long apprenticeship. You can calculate about $ 100.-- per inch for a polish, if I am correctly informed. Any amateur cleaning or polishing attempt can damage the blade and increase the costs of restoration (if at all possible). If you look carefully at your TSUBA, you will find that the soft metal inlays have been partly ground away, leaving an almost worthless TSUBA behind. Very sad! To understand all this, we recommend to read a lot here in the archives of NMB and to look at pictures of high-end swords to get an idea of good and 'less desirable'.