Ian:

Before filling mine I lock open the 4 dump valves and swab the inside of =
the valve orifice with a q-tip dipped in vasoline. Then close, pull with =
the tool & fill.

Observe for any drips. If you see any gently rub some vasoline into the =
rim of the valve (without pressing up too hard).

I've noticed that after I do this a few times - I can skip the first =
step for a few flights.

Roy B.