clean off the paint and see what colour the "weld" is,,if it is brass,then it was fillet brazed on,better to cut it off..If it is silver,,then silver soldered on,heat it up with a propane torch and it should fall off,,solder melts at a pretty low heat,wont hurt the frame.It's made to melt before the copper and brass it's used on.
I have used solder to fix chain suck on a frame a few times..
But please,,if you are uncomfortable at all,,please find a friendly neighbourhood frame builder,,I don't want anyone mad at me.!.