Several visitors made jokes about the smell. There really wasn't one - but when there are two presidents and two First Ladies in one room, the room can smell any way it wants.
Papa John is right inside the door, where as the younger Adams is a bit more tucked away - but only a bit, as this is, shall we say, an "efficiency" crypt.
It doesn't smell in this basement crypt, but even if it did, there are two presidents and two first ladies in there. A room like that could smell if it wanted to.
