HI .
All the above is correct. Protect eyes from oil.
Get your hands on a pair of long nosed pliers and gently insert ther points into two of the four holes in the botttom of the switch.
Squeeze and pull the switch out. It will come.
When out look at the seal. It should be Ok. Grease with vaseline and clean the neutral switch with some form of spirit.
But what ever you do .DO NOT PUSH THE BALL DOWN before you clean it.
Your going to get a face full of #$%*ty OIL.!! There is hardly anything to go wrong.
Replace gently, but do not touch the gear change lever whilst this is being done.
Dave Australia.