Yea, it is a pain to get it completely clean, but this is what i did. I drained the tank and took it off the mounts so it was seating on the ground. I then removed the bottom of drain bolt and took out the fuel pump. I then using a pressure washer, cleaned the tank by spraying out the first baffle by spraying inside the tank main fill hole in the tank and then working my way back to the pump hole and then flipped the tank upside down and sprayed out the drain hole. this will remove a large amount of trash. You then should put the drain plug back in and put at least 3 gallons no more then five gallons of denatured alcohol in the bottom of the tank (you can add sea foam for peace of mind is what i did) let it sit for a day and then flip the tank over for one more day. drain the tank and the tank should be clean. but you still need to clean and flush them the lines, replace all fuel filters. when you are finish you should more sea foam in the tank to run through the truck fuel system so it can clean the IP and Injectures.