Diamond rings, stuffed animals and prosthetic legs are just some of the surprising items that go on unsupervised journeys through the airport.

There are between 20 and 40 items left every day at the Brisbane Airport Corporation (BAC) domestic and international terminals – adding up to about 10,000 items a year.

As well as kindles, iPads and laptops, the more unusual items include walking sticks and even a prosthetic leg. In the change of season, coats, scarves, hats, umbrellas and jumpers rapidly add to the pile.

But what is the most left-behind item?

“Belts,” Jenni Greaves says of the most common item in the section she has been managing for BAC for 12 years and chuckles, imagining an army of passengers with their trousers falling down.

“I have this hilarious vision of hundreds of people moving all over the place holding on to their waistbands,” Jenni says.

The airport security strip requiring people remove metallic items that set off the detectors means watches, jewellery, and most usually, belts, are often overlooked as they retrieve their belongings in the rush to board. But the stash also includes a healthy selection of mobile phones –many of which are surprisingly never chased up.

Every second week, about three trolley loads of non-valuables from lost property go to the Salvation Army. The unclaimed valuables are auctioned every month at Pickles and proceeds go to charities BAC support. (Laptop data and iPad SIMS are destroyed beforehand).

There are happy and sad endings to airport lost property. Recently a newly engaged young woman left her diamond ring on the restroom basin. It was discovered by someone who gave her details to the airport staff. When Jenni connected the two by phone, she said you could hear the ring owner’s scream of delight down the line from metres away.

But when favourite and loved soft toys and clothing are left and tossed into rubbish bins, placating their teary owners is another challenge.

“We try very hard to return what are obviously sentimental items to owners,” Jenni says. One teary little boy misplaced a cap his grandfather had given him but it was gone without a trace, so Jenni organised a special BAC cap.

“It was not a replacement for what was a very loved and cherished article, but we wanted to show we care,” she said.

It’s coming into Christmas, the busiest travelling time of the year, and Jenni and her staff are bracing themselves for an increase in left articles.

“People can be very stressed and distracted when travelling and that makes them more likely to forget the extra bag or item they’ve put down somewhere,” she says. And many young children travelling now with their own mini backpacks only adds to the susceptibility.

“Please be extra vigilant about your belongings,” Jenni pleads. “Count your bags.”

Lost property inquiries at BAC International terminal tel:3406 3190 (after 12pm) and domestic tel: 3305 9233. For property left on aircraft, call the airlines.