I had a fly problem in my house (some water pipe was not being flushed often enough?). With five cats, I wanted something safer than a commercial product. I found that mixing 18 ounces of white vinegar and 2 tablespoons of dish detergent in a spray bottle quickly killed the flies. It also kills ants. Is this combination safe on surfaces that my animals and kids touch? (I do wipe down the surface after spraying.)