During the second Test between Australia and South Africa at Hobart in November 2016, television cameras captured Faf du Plessis appearing to lick a mint sweet and then shine the ball with the sugary saliva. The footage was analyzed by the match referee, and du Plessis was charged with ball tampering.
Du Plessis was found guilty and fined 100% of his match fee. He was defiant in his response, describing the charge as "ridiculous" and arguing that every team in world cricket used mint-laden saliva to shine the ball. He said it was common practice and that he had been unfairly singled out. South Africa's team backed him strongly.
This was actually the second time du Plessis had been found guilty of ball tampering. In 2013, during a Test against Pakistan in Dubai, he had been caught on camera rubbing the ball against the zipper of his trouser pocket to rough up one side. He was fined 50% of his match fee on that occasion.
The mint incident sparked a broader debate about the definition of ball tampering and where the line should be drawn between legitimate ball maintenance and illegal tampering. Du Plessis argued that using saliva (which every team did) was functionally the same whether or not the fielder had just eaten a mint, and that the rules were inconsistent and selectively enforced.