It is unlikely to be cleaned with a spatula or scraper for the first time, since putty is a very persistent material. Therefore, you need a starch solution. It is prepared as follows: add 2 tablespoons of starch to a liter of warm water and stir until a homogeneous state. Wet the roller and draw 2-3 times on the surface, then wait 30 minutes. Next, remove the putty with a wide spatula from top to bottom. If the thickness of the layer is more than 1 cm, then you can’t do without a chipper, hammer or chisel. It is necessary to knock down the old layer at an angle of 45 degrees, starting from those places where the layer is weaker. For alignment we use sandpaper or grinding machine.