The 1936 Summer Olympics practically introduced kitsch and collectibles to international sports competitions. The Berlin Games were commemorated on souvenir dishes, piggy banks, pennants and beer steins.

“The Nazis saw it as a propaganda tool,” said Jon Baddeley, a managing director at Bonhams auction house in London.

On July 25 Bonhams in London will hold its first sale devoted to Olympics memorabilia, with estimates of a few thousand dollars apiece for most of the 215 lots. They cover the modern Games, from a tattered 1896 photo of the Athens opening ceremonies through a 2012 poster by the artist Rachel Whiteread with smeared Olympic rings meant to resemble bottle and coffee cup imprints.

About 30 objects come from 1936 events. A Nazi propaganda ministry’s festival invitation is addressed to the von Ribbentrops. Third Reich eagle symbols clutch Olympic rings on glass ashtrays, white porcelain bells and steel torches made by the industrial giant Krupp.

Dozens of athletes’ medals from the past 120 years are also for sale, earned in events as obscure as tug of war, along with entire archives that the families of winners had kept together. The British equestrian Wilfred H. White stashed away a long braid of brown horsehair as a memento of his gelding jumper Nizefela. Boxfuls of memorabilia from the Australian-Canadian rower Bobby Pearce contain a commemorative beer can printed with his image.

Major exhibitions of artifacts are on view now or will open later this summer. “London and the Olympics,” at the Museum of London through September, focuses on the 1908 and 1948 games. “The Olympic Journey: The Story of the Games,” opening July 28 at the Royal Opera House in London, combines ancient Greek sports equipment and images of athletes with 20th-century medals and torches and a beat-up brown sneaker from Jesse Owens.

In April the Stavros Niarchos Foundation in Athens paid $861,000 at Christie’s in London for a six-inch-tall silver cup won by an impoverished Greek mineral-water salesman named Spyros Louis in the 1896 marathon. The trophy is embossed with motifs of swamp plants that thrive near Marathon, a Greek town. The foundation is now finalizing plans to display it this fall.

“Olympia: Myth — Cult — Games” opens on Aug. 31 at the Martin-Gropius-Bau museum in Berlin, with ancient competition relics that German archaeologists excavated in the 19th century.

“The Olympic Games: Art, Culture & Sport,” through Sept. 2 at the Bruce Museum in Greenwich, Conn., combines ancient and modern statues of athletes; vintage sports paraphernalia for Olympians and Paralympians; and a six-foot-long model of a Greek stadium crawling with tiny Sculpey competitors. Wall texts at the Bruce describe the frequent unglamorous deaths at Olympia caused by heat and dehydration.

WORLD WAR II MEMORIES

Nearly a million New Yorkers served in World War II, and millions more shipped out from local ports. In the next few months Manhattan museums will be bringing out some of the stranger battle- and home-front souvenirs.

An exhibition celebrating the 30th anniversary of the Intrepid Sea, Air & Space Museum opens on July 27, with numerous family donations, including the Marine pilot Samuel B. Folsom’s helmet, decorated with nylon stockings as a good-luck charm, and a white cotton handkerchief that gunner’s mate Richard Safran laboriously inked with drawings of warships.

The Intrepid’s collection keeps expanding by serendipity. Veterans and their families sometimes mail or drop off artifacts, and material has turned up in unexplored corners of the Intrepid itself, a former aircraft carrier.

“Nobody has ever made a systematic sweep of the ship to see what’s remaining,” said Jessica Williams, the curator of history for the Intrepid.

The museum is lending a uniform jacket worn by Lt. Harriet Ida Pickens, one of the first African-American officers in the Waves corps of female volunteers, to “WWII & NYC,” a show that opens on Oct. 5 at the New-York Historical Society. The society has also borrowed a Jeep, an air-raid siren, an Enigma code-breaking machine and a cyclotron atom smasher.

On Tuesday the society will start displaying a teaser for the fall show: one of the sculptor Felix de Weldon’s plaster models for the Iwo Jima Memorial in Washington.

At the Brooklyn Navy Yard the Bldg 92 museum is now showing shipbuilders’ 1940s tools and jewelry made from warship scrap metal.

TINSEL NOT FOR THE TREE

The American Folk Art Museum in Manhattan, which nearly closed last year, will try to entice its audience back this fall by filling galleries with tinsel paintings. A show, “Foiled: Tinsel Painting in America,” opens on Sept. 12 with about 150 pieces, mostly from a batch donated in 2009.

The paintings are actually collages of colored foil sheets, a favorite 19th-century technique among schoolgirls, folk artists, sign makers and toy manufacturers. They formed the shimmering and embossed layers into fruit, bouquets, portraits, birds, insects, lettering, flags and checkerboards. Art supply houses and book publishers offered kits with materials, templates and instructions.

The final products twinkled and reflected when viewed by firelight and gaslight. “With the foil, every kind of surprise occurs,” said Lee Kogan, the exhibition’s main curator.

Susan and Laurence Lerner, collectors in New York, acquired most of the tinsel works in the show and have paid prices into the four figures for a single piece. They bought their first at an antiques show about 20 years ago.

“It looked very strange and different, and it sparkled, and we didn’t know what it was,” Mr. Lerner said in a recent phone interview.

The Lerners assembled about 300 pieces, which required great patience; the fragile material rarely survives, let alone comes on the market. (In addition to the 2009 gifts to the folk art museum, the couple have donated dozens of tinsel works to the Kohler Foundation in Kohler, Wis., to be distributed at various other museums.) The gossamer layers cannot be restored once major damage occurs.

“If it really has smashed, goodbye,” Ms. Kogan said.

The museum has sold its West 53rd Street showplace quarters and retreated to a former annex on Broadway at 66th Street. But it is nonetheless buzzing with new energy, the museum’s board president, Edward V. Blanchard Jr., said in a recent phone interview.

The fall show is meant to be a little startling. When the public imagines the contents of the museum’s warehouses, Mr. Blanchard said, “it’s not clear that tinsel painting bubbles to the top of your list.”