Is it possible that these beads were 19th century furnace wound beads from India - Pakistan?
These kind of beads that are in my collection, collected in Afghanistan/Iran, have a slight conical perforation. Beads diameter 14-17 mm. Perforation differs from 2.8 mm to 3.9 mm. But none of the beads have any black residue in the perf as seen by modern furnace wound beads
Hyderabad with it's glass bangle and bead industry is not so far away from Iran and Afghanistan.