Here’s an old-fashioned, time-proven method to treat corns and calluses: Saturate a piece of white or stale bread with 1/4 cup white vinegar. Let the bread soak in the vinegar for 30 minutes, then break off a piece big enough to completely cover the corn. Keep the poultice in place with gauze or adhesive tape, and leave it on overnight. The next morning, the hard, callused skin will be dissolved, and the corn should be easy to remove. Older, thicker calluses may require several treatments.