When Vietnam veteran Gordon J. Castro died six years ago, his older brother, Leon, had him cremated and placed his remains in a specially inscribed, stainless-steel box.
He glued on Gordon's Purple Heart medal, his silver and blue Combat Infantryman Badge and a 1st Cavalry Division insignia.
Then he got into his Ford pickup, put the box on the passenger seat and drove from Corpus Christi, Tex., to the Vietnam Veterans Memorial in Washington to fulfill his brother's wish that he be laid to rest at the Wall.
It was hard to leave him so far from home, Leon Castro said, but Gordon had said he "left the better part of himself" in Vietnam.
Gordon Castro's remains are among scores that have been left at the Wall over the years, in gestures of devotion, but in a practice the National Park Service is now trying to stop.
With an aging population of Vietnam veterans, the 50th anniversary of the worst year of fighting and Ken Burns and Lynn Novick's 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.
Hundreds of thousands of letters, photographs, jungle boots, stuffed animals, sculptures, dog tags, college rings, a motorcycle, cigars, a piece of a helicopter rotor blade and human remains have been left.
The artifacts are gathered and stored in the Park Service's large Museum Resource Center in suburban Maryland. The human cremains are kept in a locked metal cabinet with the windows papered over.
About 70 cremains — some in containers, some scattered — have been left at the Wall over the years, said Folkerts, a curator at the resource center. The first were left in 1990, she said. The most recent appeared several weeks ago.
Thirty-one have been left in the past five years, including five in 2017.
Dick Lundskow's family and friends left two small manila packets there this past Memorial Day. He wasn't a veteran but was devoted to veterans' causes, his daughter Angela Childers said, and would have wanted part of him left there.
Some cremains are in wooden, glass or metal urns. Some are in small pill-style boxes. Some are in plastic bags or Tupperware containers, according to a Park Service list.
A 155-mm artillery shell casing said to contain the cremains of a Daniel Dhee Hughes was left in 2006.
An elegant wooden box labeled "Master Gunnery Sergeant Ronald William Looney" was left after he died in 2008. It is adorned with the Marine Corps globe-and-anchor insignia and has an ornate metal clasp.
A silver container labeled "Martin Ranko" still bears the logo of the Long Island Cremation Co. of West Babylon, N.Y. It was left Veterans Day weekend, 1990.
A small gold cylinder left in May 2011 has a taped-on label, reading:
SFC William R Shales
174th assault helicopter company
Retired 20 years of service
3 tours of Viet Nam
1937 - 2011 Rest in peace.
An envelope containing the cremains of Roger B. Probst Sr. was left June 21, 1991. Someone had written on the envelope: "You finally made it. Enjoy your reunion . . . "
Many of the containers are not marked with a name, said Laura Anderson, curator for the Mall and Memorial Parks.
"We don't have a way of knowing if it's even a Vietnam vet," she said. "Some of them could be other family members. They could be veterans from other wars. . . . We don't know."
Spokesman Mike Litterst said the remains can't be added to the Park Service's official collections.
"We're not permitted," he said. "And right now, we don't have an answer for what to do with these remains. But we do know that they won't become part of the collections."
Anderson, in an interview at the resource center this month, said: "We've been talking for a long time now about what to do about it . . . trying to come up with a policy for how we want to handle this.
"Because we're not really equipped," she said. "I imagine it's a big decision — what do you do with your loved one — especially if somebody is asking to be left here. You want to honor those wishes. But we're not allowed to accept them."
Most parks do allow the scattering of remains under certain circumstances and with a permit. But rules vary from park to park, according to regulations provided by Litterst.
Shenandoah National Park allows scattering but does not allow urns.
At Pearl Harbor, cremains of survivors of the World War II attack on the USS Arizona can be placed in urns aboard the sunken wreck. And the ashes of Pearl Harbor attack survivors can be spread in the harbor.
Yosemite National Park prohibits scattering from the air. It requires remains to be further "pulverized" after cremation and prohibits any publicity of the scattering event.
Colonial National Historical Park, in Virginia, allows scattering by air but from a minimum altitude of 2,000 feet and not over developed areas or bodies of water.
The Wall is unique.
"A lot of Vietnam veterans feel very connected to the memorial," Folkerts said. "It speaks to them in a way that many other places in the country don't. So they would like to become part of it."
Jan Scruggs, founder of the Vietnam Veterans Memorial Fund, which built the Wall, said in a email:
"Many veterans and their families want ashes spread at THE WALL and will do as they please. The vets want to be reunited with those who they remember as 'forever young' who laid down their lives in Vietnam, and to ease their pain that time cannot heal."
Leon Castro, 70, said that in the final months of his brother's life, Gordon abruptly announced he wanted his cremains left at the Wall.
Both men had served in Vietnam but had rarely talked about their experiences, he said in a telephone interview from Corpus Christi. The men and their sister, Linda, had been raised there by a single mother who worked as a secretary.
Leon, a retired carpenter, had gone to Vietnam first, serving in 1966 and 1967.
Gordon entered the Army and served in the infantry with the 1st Air Cavalry Division in 1970 and '71. He was once wounded by shrapnel in a mortar attack, Leon said.
He lived in Victoria, Tex., and worked at a nearby Alcoa plant. His sister said he was a gentle person who played the violin and did fine woodworking. He had been married and divorced twice and had no children.
But the brothers were very close.
"We didn't have a father and grew up fairly poor," Leon said. Later, "we'd go ride motorcycles all over."
When Gordon got sick, he asked to be cremated, Leon said. And "one day, out of the blue, said he wanted me to take his . . . remains and leave them on the Wall."
"I didn't quite understand it," he said. "Trying to figure out why he wanted that, I asked him, and he just said he felt he left the better part of himself" in Vietnam. "He kind of felt he died there, sort of."
His sister said he had made an emotional visit to the Wall several years ago and took rubbings of the names of friends.
Gordon died April 20, 2012, age 61.
Leon had the box specially fabricated and engraved. He drove the 1,600 miles from Corpus Christi to Washington in his red pickup. It was a two-day drive. He said he didn't feel alone: "My brother was with me."
He said he stayed in a hotel in Virginia and took a cab to the Wall.
"It was hard to leave him there," he said, his voice breaking. "I preferred to keep him close, but that's what he wanted."
Leon put the box down near the center of the Wall and walked away. Feeling a pang, he went back and picked it up, but then put it down again and left.
"I look at this as a homecoming," he wrote in a note he put with the box.
Leon Castro said he had called someone in the Park Service, he believes at the resource center, before he made the trip from Texas. He said he was told that it was okay to leave the remains.
Litterst, the Park Service spokesman, said that person was mistaken or misinformed.
Asked about the agency's new effort to halt the practice, Leon Castro said in an email:
"It is understandable. Caring for the cremains of those Vets left at the Wall is an eternal responsibility."
Correction: An earlier version of this story omitted a reference to Lynn Novick , co-creator with Ken Burns of the recent VietnamWar documentary series. This story has been corrected.