Whether diabetic or not, I would not want to be dabbing caustic fluid onto my feet, then covering it up for a few days. A self-inflicted chemical burn isn't a good way to end up.
Many moons ago, before my T2 diagnosis, as Podiatrist advised me a very effective treatment for verruca was to apply an old styleee, no-dressing patch of Elastoplast or zinc oxide plaster (just enough to cover the offending patch really) for a few days to starve the verruca of oxygen. Then it usually withers as a result.
That does involve covering the thing, so you likely don't want to dabble in anything that covers it up, without appropriate medical supervision. Aside from all else, it would be wise to ensure it is a verruca you are dealing with, and not a corn or something, where treatments are likely to differ.
Don't mess with your feet. You only get one on the end of each leg, and they're important!