elbow grease, to use

To apply physical effort. It has been said that this expression,  dating  from  the  seventeenth  century,  originally  referred  to  a joke  played  on  a  new  apprentice, who  was  sent  out  to  a  shop  to  purchase

“elbow  grease.” Originally  meaning  simply  to  use  one’s  arm  vigorously  in scrubbing  or  polishing, it  soon  was  transferred  to  other  kinds  of  effort  as well.  “Forethought  is  the  elbow-grease  which  a  novelist—or  poet,  or dramatist—requires,” said Anthony Trollope (Thackeray, 1874).