PETG feels greasy after printing

It feels like a fine film of grease, but it is not visible on the surface. If you touch the model, you can also feel it on your fingers. But it is completely odorless. I use a P1S and the phenomenon occurs on various settings with Geeetech filament. If I clean it with dish soap, the problem is solved, but a strange feeling remains. Can someone explain this? Thank you in advance!