I don’t actually agree with this, Blake, though of course there are caveats. Personally I find wood, copper too soft to budge most true verdigris (as opposed to that green waxy ‘protoverd’), and I tried sharpened copper wire and found it tended to simply burnish the surface I was working on with a thin layer of copper. I find I always come back to the same steel needle mounted in a plastic handle that I have used for thirty years, with its perfectly smooth point, and occasionally hypodermic needles with their chisel like tips . I actually find it quite difficult to mark copper or bronze with the former unless through lack of care, but a hypodermic can certainly do damage. But then again I am using a binocular microscope usually at x40 where a letter fills the field of view, and I can see exactly what I am doing. And I am happy to take many hours, and give Verdicare time to work, often overnight. Believe me, if I were to visibly damage a rare coin during conservation (for when we negate verdigris on copper alloy we are preventing future problems) then I would not do it ! But always act within your competence, and get a powerful magnifier.
Jerry