I like Microsoft mice. My current one is part of the Microsoft Wireless Desktop 2000 which is an inexpensive wireless mouse and keyboard. However, it is getting sticky, as in tacky, on the sides, where I hold it. I had thought it was just dirty, but in looking around on the internet I see that many others have this issue (also with products from other manufacturers), and that it's really the breakdown of the rubberized paint used on the devices.
I had a Lenovo keyboard at work that had this rubber surface on the wrist rest, and it was just becoming uncomfortable to use because it felt icky. I tried cleaning it with strong (91%) rubbing alcohol, but that made it way worse, so much so that I threw the keyboard away.
There are many pieces of advice out there to sand such surfaces, or use Goo-Gone, or melamine sponges etc. to remove the rubberized surface. Then I read, in a couple of places, the recommendation to use Armor All (the car stuff) on the surfaces. I decided to do that because it was non-destructive: I sprayed some Armor All on a microfiber cloth and polished the mouse with it, twice, and it has helped a lot. If it doesn't last long I'll probably try the Goo-Gone to strip away the rubber coating, take it down to plain smooth plastic.