I have been methodically hacking away at a cluster of verrucas on the ball of my foot for the past 18m, apart from a 2-3m break last summer. I have used various off-the-shelf treatments, including freezing. I have excavated untold amounts of flesh. The darn things won't shift!
It is time to escalate hostilities against my sole invaders.
But what's the next weapon in the armoury?