Kaltreiniger-more not!

I really wanted to clean my oven.
On the box I found an eco test seal "Very Good" Edition 1/2002!
Although odor is on the spray, but it smells slightly chemically.
It is a degreasing, the oven must not be preheated.
The foam adheres very well and does not break down non-more as well.
Preheat the oven I have treated twice, hardly can find a cleaning effect.
The swab was indeed black, but really Branded creates not these cleaners.
One star because the foam sticks.