gas tank cleaning

[skysoldier173rd]

Got all ready to head to the muffler shop yesterday and put about 10 gallons of gas in my truck. This was the first time i put gas in it since i've owned it other than about a gallon. Within about one minute, it stopped running and would not start. Seemed it was not getting gas. I disconnected the line to the carb and placed a clear bottle over the end and cranked it to see if the pump was working. Well, it was and i had a pop bottle of what looked like coffee, very dark brown. Filter was plugged and so is the carb now. Cranked it some more using a gallon jug and the gas now looks as it should but I need to clean the carb and get it unplugged. Figure it's the needle valve. If i have any more trouble, I'm going to pull the tank and clean it out. What's the best way to clean a gas tank? Also, after cleaning, do i need to coat the inside with any kind of shielding?