the way i do it is i take them out the car, blast them with the hose pipe to wet them, mix up "carpet/fabric detergent" add a dash of detol and a good squirt of washing up liquid (for the suds!) and using a light brush, brush into the fabric. then rinse with the hose, and repeat a few times.
when it comes to drying, i used a vax and used a portable dehumidifier and small heater (if in winter) in the car with all vents closed. it does take about 3-4 days for the car to dry out though but works.
the PiNKqCENTO i had, Talon, Alex's Marbella and one day Fallout went through the same "clean"
works well...