The present invention is a method for selectively removing objects from a surface utilizing a probe. The probe is scanned over the surface utilizing a greater and greater relative amount of force so that a certain number of the objects are removed from the surface. The force required to remove the objects from the surface can be calculated utilizing Hook's law and the spring constant of the probe. After removal of the objects that have a relatively weaker binding affinity with the surface, the remaining objects can be harvested, characterized, and subjected to further study.