Ok, that's what I was after. No flux. Do you sand it clean like you would copper for soldering?
I have brazed lots of things with fluxed bronze rods. I've repaired frozen and broken water pumps this way. Just never messed with refrigeration lines. And never used silver solder. I have a tube of it that may be very old, but it's still silver solder so it should work.
Anything else I need to know before plugging the hole?