I just wanted to post to anyone who was wondering what to do about flies. I have been using the bags that you cut the top and pull out the entrance area and add the water to the "fly bait" and the are insane! I am going through one a week. I have no flies but a bag full of dead ones. They stink for sure so place them a little further than you think you should but totally worth the $5 a bag. I have never seen a product work so well. Kudos to the inventor of this smelly disgusting product BTW...has anyone ever mixed baking soda in with the litter to help with the smell? Is it something that can be done without any harm?