I think what the other senior members said was that experimenting on the bayonet is OK. I myself liked it very much.
But PLEASE never try anything on a nihonto. It takes a decade of devoted work (10 hours a day, 6 days a week) as an apprentice for someone to be a Japanese sword polisher. And the most experienced of them take up nihonto. The antique Japanese swords are objects of art and must be treated as such. You were treated a bit harshly, because a great number of swords were destroyed by amateurs trying to sharpen nuhinto with files, sandpaper or whatever you might think. Unfortunately, an amateur will never be goodenough for a nihonto. However, if you want to practice Japanese traditional polish then you should try it on a modern production blade. There are many in the market and it will come much cheaper also.