This is a question that many people have asked, and there is no easy answer. Different degreasers work better on different surfaces, so it really depends on what you are trying to clean. Some of the most popular degreasers include Simple Green, Krud Kutter, and WD-40. All of these degreasers are effective at removing grease and dirt from a variety of surfaces. However, if you are looking for the most powerful degreaser available, then you should probably go with something like trichloroethylene or methylene chloride. These chemicals are incredibly effective at removing grease and dirt, but they can also be dangerous if not used properly. So, if you are going to use one of these powerful degreasers, be sure to follow the directions carefully and always wear protective gear.