If the line is so badly plugged it needs cleaning,i would expect the tank and fuel feed pump on injected engines would need doing too.
The best way to clean old lines on cars that have sat is to connect a cleaning gun with toluene on the front end and blow back towards the tank with a hose leading to a catch tank. I have a machine here called a carbaclean,which pumps a fluid through the system to do the same job.