For the first time since the creation, the Bouwinghausen stone memorial (1619-1635), the crucifixion group (1501), and the epitaph on the wall (1666) in the Hospitalkirche, Stuttgart were cleaned using restoring techniques. An expert from the family business Kärcher cleaned the memorials within the frame of a cultural sponsoring project. The cleaning work is part of the comprehensive reconstruction of the late medieval abbey.

Wet and dry vacuum cleaners and steam cleaners were called into action. First, the sand stone surface of the sculpture groups was vacuumed carefully with a suction brush made of natural hair and a low adjusted turbine power capacity. Afterwards, the more persistent dirt was removed gently with close to no pressure by a steam vacuum cleaner. The condensed water was immediately sucked off through a nozzle.

The challenge was to remove the dirt without damaging the original structure. The choice of the cleaning technique is crucial for delicately worked details of the hands and the faces. Of course the approach was coordinated by consulting the authorities responsible for monument preservation and the evangelical church.