Just sharing in case this helps someone or gives them a new idea. I have several rasps that I use for various curves and shaping tasks. I picked up one of these Shinto rasps for a project. It arrived after it would have come in handy but has been very handy since. I never thought about using a rasp to straighten something(?).
I used my jigsaw to cut out a template I need for something. One edge didn't turn out as straight as I would like. Blade was dull, swapped blades and the other three edges cut like buttah.
To correct the bad path I clamped the template into the vise with the errant edge in a position that would bring the corrected edge even with a piece of milled scrap.
I rest my hand on the scrap and move the scrap like a sled guiding the rasp evenly along the edge. This rasps away the high spot leaving me the nice crisp rectangle I am after.