With an aging population of Vietnam veterans, the 50th anniversary of the worst year of fighting and Ken Burns' powerful Vietnam War documentary, the Park Service said, there has been an increase in remains being left.

"It's been happening for years and years," said Janet Folkerts, a Park Service curator. "But it's becoming more and more of an issue . . . It's something that we have to definitely deal with."

This past fall, signs were erected at the Wall telling visitors that human remains "and associated objects" should not be left or scattered there, or anywhere on the Mall.

Leaving mementos at the Wall has been a tradition since the polished stone memorial bearing the names of the 58,000 Vietnam War dead was dedicated in 1982.