There are a few things you can do to clean a boat bilge. The first is to remove all the trash and debris from the bilge. This can be done by using a plunger or vacuum cleaner to suck all the trash and debris out of the bilge. The second step is to clean the bilge area with a mild soap and water. Be sure to use enough soap so that it doesn’t damage the Bilge Pump or other parts of your boat. Finally, you can use a hose to clean any areas that have been difficult to clean with other methods.