Sanding off tar

Q: We have a few areas in our hallway that the large, industrial floor sander could not reach. When these edges are sanded with a heavy-duty hand sander, the surface appears to “melt” and causes the sander disk to burn and circular burn marks appears on the floor. I think the substance is tar, which I cannot seem to remove through sanding by hand.

Can you suggest any cleaning products that will help dissolve the tar or any other way to remove it?

A: If I was doing this job, I would use a professional edger sander with a very course abrasive, perhaps 20 down to 16 grit. Very rough stuff. There is no easy way that I know of to remove this. You could try a scraper of some variety since it won’t generate any heat to melt the tar. Tough work.