with the trunk open use a screw driver to push the latch down as if you were closing the trunk
see if the light goes out on the dash. if not
press the trunk release button on the door.
you should hear the screwdriver hit a plane fling by LOL
the screwdriver is going to shoot up with alot of force.
anyway watch out.
if the light still stays on then the switch needs to be cleaned.
remove the 2 10mm bolts that hold it on
you will see the metal arm that connects to the key lock, you need to wiggle it till it snaps out.
if you try this with out removing the 2 10mm bolts you will certanly break the prongs that hold the arm to the lock assy.
you will need to wiggle the latch assy at a certain angle to get it out
pulling it twords the driverside is the only real way to get it out.
you will see a plunger type switch
notice how the switch works and you will understand what you need to sand/polish
get a piece of sandpaper any grit
and sand it slightly till its a nice copper color.
re-install and test.
should work perfect after that. will take another 20 years depending on your NSX age for it to need cleaning again.