" What is the tank made of? If
" What is the tank made of? If it is steel, I would consider replacing it, as it will only get worse and eventually fail. If it is stainless, take a large hole saw, big enuf to get your hand thru (4-5 inch) and cut holes between baffles in top of tank. Covers for these holes can be made from stainless flat stock and screwed in place with sealant, after cleaning. Make sure tank is empty of fuel and discharge a CO fire extinguisher in tank before working on it. Also remove tank if possible from boat and work outside or in a well ventilated area. If the tank is non metallic follow same procedure. I vacuumed my tank with a shop vac and then scrubbed it with a 3M pad. Nice and clean. Then vacuumed again and wiped with alcohol. Good luck, be careful and keep us posted with results. Kim "