"Hidden Message" joke

Last summer, when the power mower was broken and wouldn't run Jane
kept hinting to Dick, her husband, that he needed to get it fixed.
However, for some reason the message wasn't sinking in.
She finally thought of a clever way to make the point. When Dick
arrived home that day, he found her seated in the tall grass busily
clipping away with a tiny pair of sewing scissors.
He watched silently for a short time, then went into the house. Jane
thought she had again failed to get his attention. He was gone only a
few moments, and when he came out again he handed her a toothbrush
saying, "When you finish cutting the grass, you might as well sweep
the sidewalks."