How can I remove the old plastic wallpaper?

You have to know how to handle a wallpaper spiked roller. I was once too eager and ended up tearing deep holes into the plaster. Only gradually was I able to control this spiked roller. Slowly roll it over the entire wallpaper, and small holes are torn into the wallpaper. Then rinse, and the wallpaper comes off easily.

You definitely need to know how to handle a wallpapering roller. But a professional can do that for you.

Exactly, and here it applies: [Schuster bleib bei deinen Leisten]. But I don't understand that, after some attempts this wallpaper hedgehog can be used wonderfully.

I had no problems with it anyway.