congrats!!! I use an old toothbrush and running water to get the dirt off. Its pretty easy. Then if there is any tarnish or corrosion I rub it with damp baking soda. Some people say baking soda leaves microscopic scratches but I think it leaves my silvers looking better. If it is a key date, just use the toothbrush and get the dirt off.
Cool, well its worth a few bucks but its not going to hurt any possible collector value by cleaning it. Great coin. If it were me I would give it a nice rub down with damp baking soda. It will display much nicer and hopefully you don't plan to sell it anyway. If the black stuff won't come off easily, there is a technique that involves boiling it that is really good.