absolutely right, fell into that trap twice, Pete if he just used WD 40 and a soft cloth I don't see the damage except for the lack of red rust, which is good.
Shawn
its best to think along the lines of total preservation of the sword, IMHO its worth it, id email the bent nakago to some PPL and see what they think about the cost of fixing it. Now to some its part of the history of the sword and should not be changed.