Generally speaking, by adding an artificial environment into a suppressor, you will increase the effectiveness of the suppressor. The artificial medium, be it water, oil, lithium grease etc, will help cool the hot expanding gasses faster and make your suppressor more efficient. The only issues you should be concerned about when shooting "wet" are the effect of the meduim on your suppressor, host firearm and yourself. You shouldn't shoot aluminum cans "wet" with water. It'll corrode the aluminum and eventually destroy your can. You should also clean your firearm as if you were shooting corrosive ammo when you use water as an artificial environment IMMEDIATELY after shooting. Lastly, if you don't want it all over yourself, don't use it in your can! Some manufacturers will state that a certain suppressor should be used "wet", but most don't prohibit the practice otherwise. Just be smart about it and you won't have too many issues. I shoot some of my cans wet from time to time, and I gotta tell ya, it ain't worth the hassle IMHO. I use wire pulling gel from Home Depot (Ideal is the brand) and it works as well as anything. In my 9mm can on my AR, it splatters and spits the stuff all over hell's half acre. It's your can, try it. You won't hurt anything, but you probably won't do it much after that first time...
