Cleaning MC8 Screen

Hello I have one of the original black screen MC8 devices that I purchased right after it was released. I recently noticed that the screen was very dusty looking, so I cleaned it off with a soft cloth, but there still appeared to be a lot of dust afterward. I realized that the dust was on the screen UNDER the glass lens mounted to the case. I was able to open the unit up and clean it off, but was wondering if there was a gasket or something I could purchase and install to prevent this from happening in the future.