Can anyone tell me where I can find effective rat poison? I've tried the stuff they sell at Lee's / Hypermart. Doesn't seem to have any impact. It's for a fenced-in area. No kids or pets, so safety isn't an issue. Just want something that will actually kill the rats. I don't mind them passing through and eating what suits them. But they like using the tin roof overhang as a mosh pit, and that annoys me.