I've had to do this operation to over a dozen norcs and one m1a standard where the safeties would not engage regardless of being cocked or not.
if it's lightly sticking you can sit in front of the tube and snap it back and forth untill it smooths up.
more often than not, I just take em apart and clean up the sharp and rough surfaces of the safety hook. In the very rare case, only one so far, I had to ever so slightly reshape the safety engagement hook with a dremmel.