Oslo Council has become so desperate to stop people blocking up the drains, that it has turned manhole covers across the Norwegian capital bright pink.
Manhole covers have been adorned with hot-pink stickers, with the words "Bæsj, Tiss, Dopapir", or "Poo, Piss, Toilet paper".
A small script underneath explains that nothing else should be put down the toilet.
"We chose pink because we thought it was the best way to get people's attention," Vivi Paulsen, a senior engineer at the city's Water and Sewerage Authority, said. "It's to teach people what they should not throw into the toilet."
She said that the cost of the adverts was a fraction of what the city had to spend every year on cleaning out fat, old cotton buds and tampons from its sewerage system and water treatment plants.