I'm sure you can close the valves on both ends of the line and disconnect it. Take it out if you can or use compressed air in place to clean it out. (I don't want to be there when you do it)
What makes you think the cross over pipe is the problem? Mine is always open but the boat has a distinct list to one side after a run. It's caused by the fuel return line only going to that one tank. It takes overnight for it to equalize.
34' Marine Trader