Take a short piece of the brown or blue from a length of twin and earth flat grey cable.
Bare the end a bit, and file the tip to a chisel.
It's soft annealed copper, so won't scratch the bronze at all.
Works a treat!
I think having a divot is preferable to the horrid green colour of verd. The coin already looks considerably more appealing to my eyes after the cleaning attempt with toothpick.