I have bcome a Fan of something, but now i dont want to be a Fan of it anymore, so how do I Löschen it?

Go to 'my clubs' on your profile, find the club and click 'unsubscribe'.

if Du accidentally fanned either a CLUB oder a USER oder an ITEM Du can read how to un-fan here.
im guessing its an item Du want to unfan so thats the last one in this article, number 26!
link