Doug; There are also available small grinding stones with a wheel having a concave surface on the business end. These stones come in various sizes and grits and degrees of concavity (?) :-). I have used one for many years in cleaning up these "ridges" and the results are quick and accurate leaving a fully cleaned edge around the circumference of the capstan. A light touch is all that is needed and then regular buffing takes care of the job. Jim Bryant (FL)
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