Growing up and living in Montréal, we always had a lot of road salt and sidewalk gravel to clean up in our vestibules and foyers.   This never seemed to be a problem for our gold “fan first” Rugulator Cordaway Eureka upright from 1974.  It was always used to clean the little rug in our front vestibule and we never had a problem.  I guess the metal motor fan was durable enough.  I do remember that I would find little granules stuck in the fluff that accumulated on the ends of the brush roll chamber, but it never affected the Vibra Groomer.