Courtesy of Warner Brothers Peter Ostrum as Charlie Bucket in Willy Wonka & the Chocolate Factory (1971)

The original cast of Willy Wonka & the Chocolate Factory got their hands on some priceless memorabilia while filming — over five decades ago!

Celebrating the fantasy film's 50th anniversary and the release of its 4K Ultra HD edition this week, the four surviving former child actors in the Gene Wilder-led 1971 classic — Peter Ostrum (Charlie Bucket), Julie Dawn Cole (Veruca Salt), Paris Themmen (Mike Teevee) and Michael Bollner (Augustus Gloop) — chatted with PEOPLE about some of the goodies they got to keep from the sugar-laced set.

"I did keep a few props," shares Cole, 63, a psychotherapist who worked regularly on television after playing Veruca and published a memoir titled I Want It Now! in 2016 about her time on Wonka. "At the time, everything was just being thrown away and trashed. And I didn't have my mom out with me on location, so I was a great souvenir keeper."

She says she also "kept a couple of Golden Tickets and a Scrumdiddlyumptious bar," revealing that the cast "went trick-or-treating around the studio" and were given Wonka bars.

And as a gift for her 13th birthday, Cole — whose bratty character is booted from the chocolate factory after singing about how she wants a golden goose — reveals she was given a golden egg.

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Courtesy of Warner Brothers Paris Themmen as Mike Teevee (L) and Michael Bollner as Augustus Gloop in Willy Wonka & the Chocolate Factory (1971)

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Themmen, 61, tells PEOPLE that the cast (including the late Denise Nickerson, who played Violet Beauregarde) first reconnected in the late '90s and that Bollner "was the toughest to find."

"They put an advertisement in German newspaper that read, 'Augustus, Show a Sign.' And I don't react on Augustus, because the movie [had come out] some 25 years [before that]," Bollner tells PEOPLE.

After getting him on the phone, the cast implored Bollner, 62, to come to Boston for an interview, which was a surprise to the former actor.

"I wasn't aware at all that the film is shown anywhere," he said. "In Germany, nobody knew the film until the Johnny Depp version came [out]."

Courtesy of Warner Brothers Clockwise from top left: Julie Dawn Cole, Paris Themmen, Peter Ostrum and Michael Bollner

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Although they played rivals in the movie, Cole and Nickerson (who died in 2019) "became friends" in real life. As Cole explains, the two were "very close" and called each other "sis."

She even credits her late pal for help on a quiz show recently in which she knew the name of "The 59th Street Bridge Song (Feelin' Groovy)," due to her time dancing around Nickerson's bedroom as kids to the tune of Simon & Garfunkel's 1970 Bridge over Troubled Water record.

Cole admits that she and Nickerson — who previously reunited with the rest of the cast in 2015 — did have one rivalry, though: over the affections of Ostrum, 63, who played the wide-eyed dreamer and eventual winner of Wonka's contest, Charlie. (Today, Ostrum works as a veterinarian.)

"We both had a crush on him; he had no idea any of this was going on," Cole recalls. "I don't know when he first caught onto this — about 20 years later, I think, probably was when we told him. But we used take it in turns to see who was going to stand next to him."

Courtesy of Warner Brothers Gene Wilder (center) as Willy Wonka with the rest of the cast of Willy Wonka & the Chocolate Factory (1971)

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Today, the cast still gets recognized now and then. One of Ostrum's favorite fan encounters occurred just a few years ago, when he was at an airport in Syracuse, New York.

"There was a fellow sitting two or three seats to my right, also waiting for a plane. And we were getting ready to board and he came over to me and said, 'I just want to thank you for being a big part of my childhood.' And we just smiled at each other," he recalls.

"I knew what he was referring to, and that's all that was said," Ostrum adds. "I just thanked him, but it really brought home that there's a special place in [people's] heart for this film and that we're a part of this. It's been a really nice thing in our lives."

"Who would have thought 50 years ago that we would still be talking about this and to be involved in a project like this — that it's still relevant? It's been exciting," Themmen agrees. "Fans all have special memories of the very first time that they saw this film, and it truly means something to them."

Willy Wonka & the Chocolate Factory is available now on 4K Ultra HD on amazon.com.