Of the 15 bilge cleaners that PS tested for emulsification performance, 11 were liquids, three were thickenend liquids or gels, and one was a powder.

If you were to closely inspect your bilge and identify what ends up there, you’d surmise that what we’ve referred to in past articles (see “Do detergent and bacterial bilge cleaners really work?,” PS October 1994) as a “noxious soup” contains varying amounts of water (salt/fresh), oil, grease, fuel, and other detritus including dirt, hair, and possibly soap from the boat’s shower (if it drains to the bilge).

Much of this an be cleaned with everyday detergents, but oil, grease, and fuel present the biggest problems. None of these three mix with water, and the first two tend to act as binders for dirt. They also tend to cling to…