Each time that I return from fishing I tighten down the drag and hose it from the top of the reel with a light shower setting.  Tightening down the drag prevents water from entering the drag pads.  I then let it air dry "angled up" in a sunny spot.  This prevents water into getting "pushed" into any of the interior parts.  By the time I've cleaned the yak and all the rest my equipment, the reel is usually bone dry.
At that point I spray it down with Blakemore's "Reel Magic".  That product is readily available at most bait shops & has worked well for me over years of use.  Do not forget to release the drag as the constant pressure would reduce its efficiency over time.

On most reels there is a maintenance screw on one side of the body to add oil.  Unscrew it all the way and add just add one drop of oil.  It goes a long way.  I once made the mistake of thinking more is better and had the excess squeeze out through the spindle onto the drag bearing mechanism. Once that happens you might as well get a new one since it will cause slippage on it and the anti reverse will fail.

"Hot oil" is a brand that is widely available but Shimano does not recommend it as they have their own inexpensive Bantam oil.  You can order that from them on-line.