What is the best way to clean out a pushbutton shifter knob without damaging any internals? I just got my XT running and i need to detail it. And i need to have 4wd

To clean the switch, take apart the shifter and remove the switch, and then take rubbing alcohol and q-tips and clean it up. You should also be able to take apart the switch itself inorder to clean the contacts for it as well. That's how I would clean the switch...

Also, random tirck.... My button would vibrate at speed, so i fit a penny into the side of the button. No more rattle!

I used some of that oxyclean upholstery cleaner (comes out a white foam), to be sure I didnt wreak havoc on any plastic, then wiped the excess off and hit it with some dust off (computer caned air). I had some one sided teflon tape leftover from a 1911 safety, I put it on the sides of the button well, overkill, but it doesn't rattle anymore.

Be careful using any type of cleaner/solvant, they leave residues behind that can sometimes only be removed with rubbing alcohol, hence why I suggested using rubbing alcohol. Even grocery store rubbing alcohol shouldn't really be used on delicate electronics because it's impure, they have special alcohol that leaves NOTHING behind to clean circuit boards and other delicate electronics. Granted this is a switch and not a delicate electronic device, but still, residue on the contacts can create a bad connection and cause the switch to not work, even though it appears clean. Doesn't happen very often, but can happen. If you do use a cleaner/solvant, you can rinse the switch with distilled water and let it air dry, and that might clean of any residue that is left behind, but not guaranteed. Hard to say, but can't hurt it. My 2 cents.