Short what? I don’t understand (yet).
The nozzle has a ring lug with a star washer, presumably that’s the contact for the touch to level.
There are two fine wires under the little squirrel cage fan, probably for the thermistor.
And there are a couple wires shrouded in some red silicone wrap, I think that’s for the heater.
All the wires are insulated as far as I can tell.
I guess if you got aggressive with wire brush you could wreck something.
I heat up my hot end and clean it with a dry paper towel and a glove.
I’ve never worried about grabbing a string off the hot end with the metal tweezers. I had a “poor bed adhesion” the other day that left my print head covered in PLA. I wiped most of it off while hot without a problem. Yeah, there’s still some in certain areas I couldn’t reach, and it will be there until I can get to it.
If you short the nozzle to the chassis, it’s just the same as if had hit a limit switch. The four washers are connected to chassis. When the unit is on, there is 5V through a pull-up resistor on the print head.