akr, I've always just used a damp rag to get mud and dirt off mine. The metal gets the normal gun cleaning stuff. I don't know what's in the oil soap, so I'm sort of leery on using it.
k96, if your planning on getting wet (duck hunting), I'd take the stock and forearm off and seal the interior portions with polyurathane. For normal use, the paste wax on the wood and metal works wonders for rust prevention.