Origin of holystoneprobably so named because the user is on his knees
transitive verbho·ly·stoned, ho·ly·ston·ing, ho·ly·stones
Origin of holystonePerhaps from a sailor's kneeling position while scouring with the stone.
Smaller blocks for awkward places are prayer books.
(third-person singular simple present holystones, present participle holystoning, simple past and past participle holystoned)
Uncertain, but likely from the fact that scrubbing is done while down on one's knees, just as in prayer.