I'm working on a 73 Satellite / Roadrunner that's been sitting in a field for 15 years after I pulled the motor I noticed what looked like melted black plastic on the floor after seeing it a couple times I realized it was coming from the fuel line. I had some on my fingers and it washes off with just water. It's still coming out of the fuel line so I know it's not hard yet but what's the best way to clean this stuff out plan to pull the tank remove the sending unit and dump out as much of the crap as I can and blow out the fuel lines with a blow gun but what will get everything clean enough for a new motor? carb cleaner? Sea foam ? paint gun cleaning solvent? what do you guys use?