Noted. I will take a very gentle, non-rubbing, no brush, mostly dry dabbing approach to cleaning the tsuka-ito. Inspecting as to look for possible damage. Less is more in this case so that it is better to leave it more dirty than clean as a professional restoration would be ideal so, don't screw up anything that can't be undone.
If you think about it this sword made it through a war, a transit to America, 80 years of who knows but likely storage as the blade is undamaged, the compaction unit in a garbage truck, and a large loader grapple. It was 40 feet away from a industrial sheer shredder and it will now be placed on the wall of a conference room. This sword is a survivor!
This has been a great response from a passionate community of individuals and I greatly appreciate all the information and history you have so kindly provided. I will take some before and after pictures of the cleaning and provide an update.
Thank you all again!
Jeff