Equipped with music players, automatic flushes and heated seats, Japanese toilets are clearly not afraid to cause a stir with their innovative designs.

But these cutting-edge seats have an unexpected nemesis: toilet paper.

Toto, Japan’s top toilet maker, said last week that users should not use toilet paper to wipe toilet seats as it could cause micro scratches on the surface.

The company made the recommendation after a series of posts on social media complaining about scratches and discoloration.

A Toto representative told Japan’s Mainichi Shimbun that its bidet toilet seats are made of plastic resin because the material is “resistant to detergents and capable of being molded into complex shapes.”

However, wiping the seats with toilet paper or a dry cloth may cause small, invisible scratches where dirt can accumulate, causing discoloration.

But Toto isn’t the only manufacturer to advise users not to use toilet paper to wipe toilet seats.

Cleaning experts have previously posted similar advice, as well as on lifestyle websites.

People recommend using a soft cloth soaked in tap water or detergent instead of dry toilet paper. They also recommend not using thinners, nylon or metal scrubbers, or abrasives—all of which can damage the surface of the toilet seat.

The company said that while it is looking for a more scratch-resistant material, it has “no current plans to change this material.”

Toto’s flagship bidet toilet Washlet includes features such as an automatic lid, air dryer and bidet flow pressure control.

Considered an extension of the country’s hospitality culture with their thoughtful designs, Japan’s toilets have become unexpected tourist attractions for foreigners and a source of pride for Japanese people.