More than 100 eco-friendly Olympic medals won at the Rio Games last year have been sent back because they are rusting and decaying.
The medals were hailed as a masterpiece of sustainability because they used recycled materials in place of traditional precious metals.
However, less than 12 months after they were handed out, a substantial number of the prizes are already the worse for wear.
About 150 of the medals – particularly bronze ones – have gone wrong since the games ended last August, Brazilian officials have acknowledged.
Athletes report that the items – which likely symbolize the greatest achievement of their lives – have started to flake, rust and develop small black spots.
Environmental advocates were thrilled with the original medals for their green credentials.
Bronze medals were partially made from copper industrial waste, while the “gold” medals are actually recycled silver, plated with 0.2 ounces of actual gold, accounting for 1.2% of its total weight.
However, they seem to be struggling to stand the test of time.
Some athletes reported that they had stopped letting people handle their medals for fear they will tarnish further.
One told The Times of London: “If I’m out showing my medal to kids, I try not to give them that one to touch in case it gets worse. I tend to let them hold my London  one, as it is much better.”
An Olympic spokesman said between 6% and 7% of all medals had been affected. 2,488 medals were minted, meaning that at least 150 have now gone bad. More could follow.
A spokesman for the Rio Games claimed that most defective medals had been “dropped or mishandled”, or kept in inappropriate temperatures.
It is not absolutely clear whether the production materials led to the increase in tarnishing – though the issue has not arisen among medals from previous games.