Old Pa Jones tells old Ma Jones that he's going into town to apply for social security. Ma says, "But Pa, you don't have a birth certificate. How are you gonna prove your age?" "Now don't you worry, Ma." said Pa, and leaves for town.
Sure enough he's back in a few hours and reports that he'll be getting the first check in three weeks. "So how'd ya prove your age?" asks Ma. "Easy," says Pa, smiling, "I just unbuttoned my shirt and showed 'em all the gray hair on my chest." "Well, while you were at it," Scolds Ma, "why didn't you drop your pants and apply for disability?"