Thanks LapLap--will report back when I check one or two out , but not till May! (I just like to pre-plan!)

Edited May 22nd-here's my report.

Went to this one http://www.yurax.jp/. Little tricky to walk to it due to the convoluted nature of the roads near there, but with my trusty Tokyo atlas in hand , I made the trip on a Monday evening. It is definitely a local sento, buried away on a small back street and it is combined with a mini-convenience store, and a small laundromat. I am sure they don't see many western visitors.

Paid the required fee, and bought some soap and shampoo. Had my own towel, but if you don't they sell "empty handed sets".

Water temp was quite hot and there was a hot, medium and cool bath. Did not try the sauna.

Good way to relax for a bit for a nominal charge.