FWIW, the Technoid at
http://www.shotgunreport.com/TechTech/TechnicalTracts/CareClean.html
has this to say "...For you socially irresponsible proponents of the gas gun, the
Technoid has one basic recommendation: Shoot them wet and clean.
Both Beretta USA and Remington will tell you to shoot them dry. They
are wrong. Who you gonna trust- your gifted gun guru or the people
who merely made the guns? Slather up the pistons with BreakFree CLP
(the brand is important) and leave them good and wet while you shoot.
Not only do the gas guns function better when wet, but when cleaning
time comes around each and every evening you will find that the
BreakFree has kept the burnt powder residue in solution and most of the
parts can be wiped clean with a Kleenex. Shoot them dry and that
carbon is going to be burned on. It is interesting to note that Beretta of
Britain used to recommend shooting their gas guns dry, but now has
recanted and recommends that you shoot them wet. Toldyouso. As
usual, Beretta USA does not have a clue..."
--Daniel