This is a process from a very well respected person who has been in the detail business for many years. This is a quote from another forum on his process that he indicates is fool proof and easy. I've never tried it because I have a Turbo Nozzle attachment on my vacuum that removes everything and anything.
Want a really easy way to get the hair to release and be sucked up in the vaccum?
Most of the hair is held by a static charge generated by the types of artifical fabrics used in vehicles.
Buy a can of the cheapest aerosol "anti-static" spray you can find and mist the fabric or carpet, give it about a minute, then vac the fabric/carpet.
If some still remains, and doesn't it always, brush the area in "one way", aligning the fibers, remist and vac in the same direction.
It's gone!
Another way, but not quite as effective, is by a bottle of fabric softener that says "anti-static" on it, mix it about 20 to 1 and use it.
Not as effective as the aerosol, but does help.