Magistrates have fined a man £200 after finding him guilty of putting paper in a recycling sack for bottles and cans only - breaking council rules.
Michael Reeves said the decision to prosecute him was "crazy"
Michael Reeves, 28, a journalist from Swansea, had denied putting an item of junk mail in the bag.
The court was told the letter, which was addressed to him, "contaminated" the other items put out for recycling.
After the hearing Mr Reeves said he had since stopped recycling and feared his case would discourage others.
Magistrates in the city were told under the Environmental Protection Act, councils could impose strict rules on their refuse collection services.
Mr Reeves was served with a warning notice in April this year when he put his bins out a day early because he was going on holiday.
Then in June a green recycling bag was found outside his ground floor flat in the Mount Pleasant area of the city containing both paper and bottles and cans.
Swansea Council enforcement officer Martin Lemon said: "There is a recycling scheme available in which paper can put into a green recycling sack and glass bottles and tins can be put into a separate sack."
He said if the items were mixed in the same bag then it would be sent to landfill instead as the council's recycling collection team refused to pick it up.
"The fly-tipping team have responsibility for collecting waste that has been incorrectly disposed of," he said.
"The teams are trained to search through any offending waste that they have found to look for evidence of its origins.
"My colleague informed me that he had opened a green recycling sack and that he found a piece of junk mail with Mr Reeve's name and address."
The sports writer with the city's Evening Post newspaper denied putting the letter in the bag.
The court heard there were no eye witnesses or camera footage of him doing so.
His solicitor Nicola Smith said there was "an array" of possibilities of how it came to be in the sack.
But magistrates found him guilty and fined him £100 and ordered him to pay £100 costs.
Speaking after Tuesday's hearing he described the case as "crazy".
"I don't believe they proved beyond reasonable doubt that I put the paper in the bag - I did not," he said.
He added: "I have not recycled since I received the summons.
"People are not going to recycle if they end up in court and it costs them £200."