Which preposition to use with inkstain

of Occurrences 1%

All the inkstains of his youth had been obliterated, and those nails which had once been bitten to the quick during the throes of financial study were now things of beauty.

on Occurrences 1%

For the new Royal College, having as yet no buildings of its own, now keeps school, it is said, thereinalas for the inkstains on that beautiful floor!

Which preposition to use with  inkstain