Old-timey Saying

  He was regretting the loss of what he used to have somewhere back in the expanse of his six years of memory.  I told him there was an old-time expression to deal with that:  "There's no use crying over spilled milk."  Back in the old days, I told him, farmers used to milk their cows by hand, into  a bucket, which the cow would occasionally kick over with her foot.  The precious milk would be lost, and the milker (or milkmaid), would be distressed.  But once the milk was lost, there was no sense in feeling bad about it.  What had happened happened, and nothing could change it, so it was time to move on.  So did he understand the expression?  "Oh, I get it," he said, "Every time milk gets spilled, you've just got to clean it up."