A few years ago I bought one of those boxes that you plug into an electric outlet. I think it is called Ridex. Anyway, it is a rodent and pest repeller. I can seriously tell you that since I bought it, I have not had any big black spiders. I may find a few spindly daddy long leg type, but not the ugly, hairy black ones. I also have not had centipedes either. And no mice. It was definitely worth the $13. I got it at a kitchen store in the mall.