When i first started out in paintball my first gun was a Spyder TL plus and i use to clean it by dunking it in a bathtub of water and moving it around in the water.
Apparently this is OK for Mags, not sure about firing it though. As long as it's gassed up this will stop water from getting to parts that it shouldn't. If you have a leak as well, it will make lot's of nice little bubbles too!!!