Thanks for your answer!
I was in a shop to buy some stuff which I probably can use. But I didn't buy WD40... Really dont knoe what to think about it, a lot of people say you shouldn't use it, but at the same time there are a lot of cyclists which use it.
One product i bought was "1-Step Cleaner & Lubricant" what do you think abt that? and just a bottle normal "bike cleaner"