Is it possible to remove fluid trapped behind eardrum? How?

Fluid. Fluid can be pushed out by popping the ears (valsalva manuever). If you can get the ear to pop then you are forcing air up the eustachian tube into the middle and simutaneously forcing fuid out the tube. Afrin (oxymetazoline) and sudafed help open the tubes. Also, sugery to puncture drum will allow fluid to come out. Often a pressure equalizing tube is put in to keep the drainage port o[pen for several months.