Which preposition to use with scratchings

of Occurrences 29%

The scratching of my pen deafens me ...

on Occurrences 9%

A scratching on the canvas, the Northern knock at the door.

at Occurrences 8%

The second night, as I lay sleepless and desperate on the strip of dirty matting that served as bed, I heard a scratch-scratching at the grated slit of a window, and presently a slender stick was inserted into the cell.

against Occurrences 1%

Never once during the day was there a sudden or unexpected sound, whether the snapping of a burning faggot or the scratching against the rock of a log rolling apart, or the flap of her canvas, that she did not look expectantly toward the rude door through which she thought to see him returning.

for Occurrences 1%

Instead of spending all his time and strength in a constant scratching for the food of to-day, how soon will he have a blanket of skins, and a hut, and a garden in which he is preparing to-day the food of future months.

Which preposition to use with  scratchings