I've used Nature's Miracle, Simple Solution, the off brand sold at Wal-Mart, the citrus stuff sold at Wal-Mart, and vinegar/water. Most of the time now I just use vinegar and water and honestly think it works just fine. In my old apartment, there was an area under the puppy pad that got completely soaked down into the carpet. I used vinegar/water, let it soak for a day or two, put baking soda on top when dry and then vacuumed. It worked