A gritstone for erasing the marks on a stone.

plural of rubbing alcohol

present participle of rub up on

(uncountable) The technique of making a paper copy of a brass-plate engraving by placing a sheet of paper over the plate and rubbing with a crayon. / (countable) A copy so created.

present participle of rub up

plural of rub-off

Alternative form of ruboff

plural of rub up

That is where the problem is.

(idiomatic) To make an injury, physical or emotional, feel worse.