how do you remove unleaded fuel in diesel tank?
Drop the tank and clean it. The lines may need to be drain also if it made it to the engine.
We recently put unleaded gas in a diesel powered car while traveling in the United Kingdom. Watch out, their pumps for unleaded are covered with a green jacket on the nozzle, the same as diesel in the U.S. There are over a 120,000 people that require a fuel vacuuming every year hence a need for a mobile extraction service. The van comes to you hooks the fuel system up to a pump and has you back on the road in 20 minutes. I don't know if this service is available in the U.S. but it sure beat dropping the fuel tank.