This actually sounds really dumb. You risk getting everything wet, and you will have to wait a couple of days to see how it didn't work. Ethanol is a really poor solvent. Just get a lint-free cloth, wet it a bit, and rub the mouse over it for a minute or two (holding it upside down).
Another thumbs down from me...Ethanol is just going to dry out the natural oils in the rubber and attract more skin oils and dirt...
I use the lint-free cloth method as well. Although in the comments one guy mentions using a toothbrush...I might give that a try if the lint-free method ever fails me. Not going near the ethanol though.
It seems like Acetone would be better off. It dries instantly and supposedly cleans.
Plus getting 190 proof Ethanol or Everclear (190 proof Alcohol) is illegal in a lot of states cause its the stuff that they make crunk juice from (ohhhhh....).
So I think this is a slihgtly shortsighted and risky endeavor. Im sure as hell not doing it.