I saw Reagan's hand once
His motorcade was coming up 6th Avenue in Manhattan and I saw the limo and a hand waving out the partially open window, which I assumed was his. This would have been during his first term.
I also saw Bill Clinton coming out of Blair House, around 1995. He was with a group of people who I can only guess were foreign visitors since that's what Blair House is used for. They crossed the street and entered the White House grounds. Clinton was very tall.