sounds like the o-ring in the oops has gone bad and/or dry.
grap the pin in the airport with either a small socket or a pair of pliers (not the greatest tool to use but may be all that is to hand)
now unscrew the on/off knob and that should unscrew the pin too.
once you get the pin out look in were your bottle went and there should be a brass plate that you can remove with an allen key, take that out.
now you should have the oring exposed (a 007 if i remember correctly), take it out have a look, replace if neccerssary and lube with any dow33 based greese (money spunk FTW)
put it all back andit should hopefully work