Dilute Universol concentrate with water in a ratio of 1: 100 for slightly soiled surfaces such as nicotine scale. Dilute a maximum of 1:10 for heavy pollution.
Then apply the mixture to the contaminated surface with, for example, a sponge or brush. Allow to work in for a few minutes but do not let it dry.
You can also use the ready-to-use spray. This is diluted for you 1:10.
After Universol has acted for some time, once again use the sponge or brush to "move" the surface. As a result, the pollution is absorbed into the liquid. Now take everything off with a clean cloth or clean sponge and dry the surface.
Finally sand the surface and make it dust-free. You can now start painting.