You had earlier asked about the peculiar scratch marks on pallava cave walls. Was reading sir k r srinivasan's wonderful book : the dharmaraja ratha and its sculptures. He describes as below
The final surfacing was done by incising a series of long parallel lines followed by feathering strokes, between the close set lines using different kinds of chisels with the hammer ( kodutal and karaittal). The evenning out and sommothening that gave the finish were done by light and close pecking strokes with the pointed chisel ( politel or plichchal) and subsequent tapping strokes with a flat edged chisel having many prick like dentures (palamunai)