After you pare down the callused area, you should see punctate hemorrhaging. At this point, you will see a fairly clear delineation of healthy tissue vs. infected tissue (it looks kind of like a plug of skin with a roughly circular, demarcating border). Using negative pressure with the hand holding the spatula (such as your hypothenar eminence on the sole of the foot), you can gently push down around the delineated periphery and move the spatula around the entire circumference. I say gently because it's not unheard of to push too hard and insert the spatula a bit too far (ouch). After traversing the entire area, you then push the spatula horizontally at the base of the lesion to completely free it from its attachment. There will be significant bleeding bedause of the neovascularization so prepare with an absorbant drop cloth and plenty of gauze. Your job now is to make sure (as best you can) to destroy all infected epithelial cells. I like using phenolic acid with a long cotton-tipped swab. Also, make sure to wash out the newly formed hole with saline to both counteract the chemical action of the phenolic acid (though, the hemorrhaging will also do this) and to further flush the wound.
Using a spatula has always worked for me, although the virus sometimes escapes my wrath and returns. A blunt spatula is more than adequate to remove the lesion. It is absolutely vital that you do not use a sharp instrument because, 1). You are only concerned with the epidermis - not the dermis, and 2) If you damage the dermis, you will likely get a scar out of it, which will act like a permanent verruca plantaris. This sucks for the patient.
