I've been trying to find an honest one since 2008, but I have to be honest: In the MAK museum, a very nice lady told me: it definitely has to be professionally removed from the clay, the chemicals in the cardboard would make it crumble more, which costs 600 euros here. I'll never forget this declaration of love in Austria, it didn't happen to me very often! Maybe my timing was good and she was just horny, I don't know. Too bad. ((Mexican tourist souvenirs would be thrown out of the window))