Sorry if I'm teaching anyone to suck eggs here, but I got my windows back up to speed with the following:
1. Door card off, open the window and spray dry lubricant on and into the rubbers and wipe with a rag. Repeat until the green/grey muck is gone, then spray and leave in. Important you then close the window and do the lower section of the rubbers inside the door cavity.
2. Restore the current getting to the motors by cleaning the contacts in the switch box. This is easy but fiddly (bits jump out when you open it) and there's a detailed how-to on this forum.
3. Driver's door only (as it suffers the most wear), replace the brushes in the motor. This can mean having to take the whole assembly out, but depending on the variant you might be able to get at it without. Mine were knackered so had had to scavenge from Julian V while he was servicing my truck but normally you could just swap with a rear motor to extend the life of the driver's window.
New rubbers aren't a bad shout and obviously this saves you doing no. 1, but I can't imagine you'd get best results without doing 2 and 3.
Cheers,
Guy
Sent from my HTC One_M8 using Tapatalk