★★★★★
A therapist called Dr. Harvey Kaltsas describes how to use it on page 8 of his piece on natural oils of chinese medicine.
It apparently works in a few weeks when used nightly. It removes hardened masses too and he says "works to moisten the tendon sheathes so they move smoothly and allows the fingers to open and close without catching".
Anyway you can read more if you google the oil. Hope that helps!