Not sure if I reinverted the wheel, but after draining my central heating
system to allow me to do some soldering, there was still water in the
pipework near where I wanted to solder a new joint.

To clear it I did the following:-

Cut a hole in the side of an empty 2 ltr drinks bottle,
Removed the screw top and connect the bottle top to the pipe using a short
lenght of hose,
Laid the bottle flat, rotating the bottle so the hole I made was facing up,
Switched on a dyson vacuum cleaner and held nozzel close to hole in side of
bottle.
Water was sucked into the bottle, but wasn't sucked up into dyson nozzel.

The drinks bottle crumpled up a bit, but I still managed to completely clear
the pipework of about 6 pints of water in no time at all.

Darren.