by Time Slot » Sat Oct 06, 2018 6:49 am
John,
I am new to the forum too but have been into horology for many years so maybe I can help here.
Yes you can use 91% but I would recommend running the parts through some type of dryer box or at least use a hair dryer on them after the rinse. 91% is far far better than using only water. Of course the higher the alcohol content the better but if you do a decent job drying the parts you should be fine.
James