if you clean it on the white paper you have a good result the first time but you will damage it doing it several times... my old mighty mouse doesn't work because the scrolling ball has damaged a little piece of plastic inside the mouse.
my second mouse works perfectly since 2008 because every 5/6 months i open it and clean the internal parts just with my fingers, without alcohol or other stuffs... every time i need to break the lower side with a cutter but i always fix it with glue when i finish to clean...