Namaste @anwenbaumeister,

Everybody make sure your nostrils are clean and free of boogers before you inhale and exhale. :P

This was quite famous a few years back here at Nepal. A famous Yogi called Baba Ramdev (He is quite famous in India and Nepal) taught this aasan on TV. He called this aasan Anulombeelom. I have never tried it though. I'll give it a try in the evening if I remember. Another one was called Kapaalvaati in which you had to rub the tips of your fingers together.