Lets start my 2nd grow:
Step 1: I used denatured alcohol (Brennspiritus) to clean the glass.
Step 2: Flushed the glass with distilled water (Destiliertes Wasser).
Step 3: Put this new baby in distilled water (Destiliertes Wasser).
Seed is now in the dark* at 21°C and 100% humidity.
*https://www.youtube.com/watch?v=ZDrlmlzY7cE
After 5 days, the seed didn't pop-up, so I decided to change the germination method and put it into a wet paper towel. One day later it popped and the first little root emerges.