Yeah, as long as you're happy going through the motions to use it then that's your call. I think that sounds like there might be something else going on which could be some concern, all of the gunk inside is probably a good hint that something worse might be waiting inside. Sugar ants are attracted to computer boards due to the heat they produce, for instance, and they can nest inside electronics. If you want it to keep working I'd suggest you get yourself a proper screwdriver for it and open it up just to double check. A search on the net will suggest how to open it up safely, no doubt. If you do open it up and it's in need of serious cleaning, a lint-free/static-free cloth with some isopropyl alcohol should be the way to go. Just very lightly brushing anything off with that will likely be enough. Electronics are obviously delicate to a certain degree, but so long as you work on it and you're not on a carpet or in a very humid/ionic atmosphere you should be all right. Just keep a container handy for any loose screws and make sure you put it back according to spec.