Watch List notes:

Potosi, Bolivia, cob 8 reales, 1660E. S-P37a; KM-21; Cal-1524. 23.61 grams. Very heavily worn (Fair) yet with full pillars-and-waves and cross, three dates and two assayers, richly toned. Possibly shaved around the edge to account for the light weight, but more likely this was simply one of those coins subjected to "slinging," where they were whirled around in a canvas bag for a long time and then the bag was burned to yield bits of silver for the "slinger"!
($100-$150)