Jae C. Hong/Associated Press

Over 100 medals won during the 2016 Summer Olympics in Rio de Janeiro have been returned to the Brazilian Mint because of rusting and the development of black spots.

On Friday, Andrew Downie of Reuters reported at least 130 medals have been returned, most of them bronze and some from the Paralympics. The Brazilian Mint is repairing the medals and will then get them back to the winning athletes.

Rio 2016 communications director Mario Andrada revealed the reasoning behind the medal problems.

"The most common issue is that they were dropped or mishandled and the varnish has come off and they've rusted or gone black in the spot where they were damaged," he said. "The second thing is that a small few, about 10, had problems with the extreme cold."

Andrada also called the issues "completely normal."

Per Downie, 2,488 medals were made for the 2016 Summer Games as well as "hundreds more for the Paralympics."