SOM Berthiot Cinor lubricating

[joelpierre]

I acquired a Bolex H16 Reflex (1957) with three lenses SOM Berthiot Cinor (Cinor 10 mm f/1.9 RX, Cinor RX 25 mm f/1.4 and Tele-Cinor 75 mm f/2.5).

http://www.bolexcollector.com/cameras/h16reflex.html

http://www.bolexcollector.com/lenses/50berthiot.html

It seems that everything is in very good condition, but the adjustment ring distance of the lenses are very difficult to turn.

I guess it is the original grease which has dried.

How can we fix this?