According to the Thursday edition of daily paper Berliner Zeitung, the rough slabs of granite, chosen for recent renovation of the busy area, is nearly impossible to keep clean with normal methods.
Now the city's BSR cleaning service will use a new device that will blast the granite free of what hundreds of thousands of commuters leave behind every day.
“We'll try for the next year to see if the wet cleaning will be a permanent solution,” Ephraim Gothe, an official from the Mitte district, told the paper.
The special cleaning takes up to five days and costs €10,000, so it will only be done four times a year.
Chewing gum poses a bigger problem than other types of filth such as grease from discarded bratwurst. City officials are trying to find a better way to remove the gooey wads than the current method – freezing with nitrogen and then chiseling them off.
“We're testing different technologies – high pressure, steam jets, or icing – to see which works best against chewing gum,” said BSR spokesman Bernd Müller.