1. duplicate layer
2. blur (until blend well all the hair)
3. change blend mode to Darken
4. make a stamp layer (cmd+alt+shift+E)
5. High Pass (same value as the blur)
6. adjustment layer Threshold (somewhere between 123-127 depend on image and resolution) must see all hair black & white)
7. go to Channels and cmd click on RGB composite
now you have a selection of a hair (but not only). Invert selection.
8. create a Curve adjustment layer (double click on mask and ad 1-2 pixel on Feather)
9. delete all unnecessary layers (blur, HP, Threshold)
10. play with curves until al black hair vanishes, and put in a group with black mask
11 brush with white on a group mask (keep distance from the edge and other area you don't want to clean)
take 3-4 min
can make an action for this, and finish in… 1 min
I use in 90% of cases. in 10% I use FS.
cheers