If that switch gets too bad, it can start causing lots of other problems. Things like the transmission not wanting to shift correctly.
Maybe you could try going to a shop with an air compressor and blowing compressed air around the small gaps in the top of the shifter and see if that helps. I wouldn't try anything but compressed air, any type of cleaning fluid may just make it worse.
I forgot to mention before that I don't know the part number. You can try ordering it from Fastlane, I'm sure Phil can look it up.