Volvo Repair: Flush Gas Tank, gas tank, fuel filter

Question
I have a 1990 740 STD Wagon.  Someone emptied the contents of a fire extinguisher into my gas tank.  Is there a plug to easily drain and flush the tank?  or should I drop the tank and flush it that way?  Any advise on this fix it job would be greatly appreciated.

Answer
Hello Mike,
          WOW!!Sounds like a long story.
            I guess the best way to resolve this is to
yank the tank.My guess is that this material is abrasive and you don't want to rely on the fuel filter to do the job.So Mike,you gotta do it right that means the tank has to be fully cleaned...If you count on the filter to eliminate ALL of the material..you may still get material to the the engine.You will cause damage if this occurs.
            You should consider what you will do to the old gas.
             Good luck,
                        Bilbo