I cleared a similar problem for a fellow camper just last week. I used a coat hanger hook, but instead of hoping to get the hose back on in time, I poked a tiny hole in an old hose connected to the outlet and the dump station. I worked the coat hanger through the hole in to the tank and after a bit of poking, pulling, and twisting, the clog broke free and the tank emptied with out a drop spilling. The little hole in the hose probably could have been fixed with a dab of glue, but the owner elected to toss it instead, since it was spare that was pretty beat up anyway.