resistor tampering

[foTONICS]

so a couple years ago during my DC final a bonus question asked:

If you scratch the material off of a resistor with a knife until you see bare wire, will the resistance go up or down?

almost everyone answered down but the teach said the resistance would go up. can anyone explain this to me as it still doesnt make sense, and neither did his explanation

 

[BobK]

Don't think of resistance, thing of conductance. How could taking material away make it conduct better? This is what you (wrong) answer implied.

Bob

 

[foTONICS]

thanks a ton bob that makes perfect sense, i was thinking of the material as slowing down the conductance not enabling it