How not to Treat Callus
There are several things you should not do to treat a callus.
Do not treat a callus until you are certain that it is a callus. If there is doubt, see a podiatrist.
Do not attempt to cut out callus. "Bathroom surgery" can result in injury and infection.
Do not use metal callus files that resemble cheese grators. They can gougue and shred the skin,
Avoid medicated corn pads. Medicated corn pads are dangerous because the "medication" is actually a strong acid, which can burn the skin and cause an open sore. Often, medicated corn pads also burn healthy skin around the calluses.
Slow and steady treatment methods combined with pressure relief are the safest ways to treat calluses.
Reference: Great Feet For Life: Paul langer, DPM