At one account, a restaurant, the flies are more in the kitchen and less under the front counter sink. Had some in the bathroom but got rid of them. These flies are a little bigger than the fruit flies. They act like fruit flies. Are attracted to beer, sinks, and water in general. I have tried the blue sink drain liquid. I forgot what it's called right now. That did not work. They don't appear to come from the drain. They are definitely near the fruit, and dish washer area near the fruit. Ive told the owner to put the fruit in a closed container. He says it is not practical for his operation. I know the owner should "clean up" his act. However, is there something I can do, to get rid of the problem? Tried glue traps also. At my residential accounts, a little red wine vinegar with dish soap works all the time. I only have two commercial customers. They both have similar problems. I would like to get more. But, this is stopping me from trying. Anyone have a secret weapon they want to share?