As mentioned, a piece of hacksaw blade is a wonderful tool. Needless to say, I took a hunk out of a hacksaw blade. I chose a place that had a hole in it so I would have a hook. The side away from the teeth was sharpened. And the piece was epoxied between pieces of tongue depressors and those were profiled.

The sharp side cuts in, the teeth hog out, and the hook hooks stuff.

I don't know how old this tool is, but it's going to be around a bunch more years.