whats the way to remove scratches from knife blade?

Answer 1

I have heard that rubbing the knife with aluminum foil will help to lessen the scratch. I, personally, have never tried this, so I cannot attest to it's correctness.

But it's worth a try.

Answer 2

Try polishing with a fine grade of jeweler rouge. It will take a while depending upon how deep the scratches are. If they are very deep use a buffing wheel on a bench grinder with jewelers rouge.

Jeweler's rouge is available at most hardware stores and home centers or where tools are sold.