Given the amount of metal and bad stuff you should most definitely not just put them in the Kehrichtsack (or rubbish bag for our many forum readers who do not speak German). Usually there should be something written on the recycling information supplied by your community for "Kleinmetal" (small metal). In my case I have to take it to collection point nominated and they will take it. I think there is a very small charge depending on the weight, but at least you won't have to feel guilty