rinse that tank with water a few times. Use a bbq long lighter to test and or 'pop' any pockets of fumes. bare the accessible side, rough it up real good. Apply flux to the damaged bare area. Take the propane torch to it, and flow in 60/40 thin rosin core electrical solder. You wont need as much heat as brazing, and it works fantastic.
Liners, even the good ones, are for quitters.