[Russ Noble]

Simon, water helps, but a better way is to purge the tanks with exhaust gases. Hook a hose up from the tailpipe of a car into the tank/s and run it at moderate speed until the tanks are almost too hot to touch. This will completely purge all the fumes out of the tank and also evaporate any small residues of fuel trapped in seams etc. This method is the best I have used. No problems.

Cheers