I know this post is years old, but did you ever get rid of them? I am an American living in Sofia and I have the same problem!! I don't know what to do. I don't leave food out, I know where they are coming from so I sprinkled/emptied containers of salt and baking soda because the pharmacist told me this would work. It doesn't. I've gotten a bit crazy and now I am barely even eating in my apartment and still they come!!! Where do you find poison even? I have yet to find a store around me selling anything like that. Times like these I miss Walmart.