If the callus is causing you
If the callus is causing you pain, then try to wear it down with a pumice stone. If they don't cause pain, then don't worry about them.
The callus could be an indication that something is wrong with your form. You are pushing off or sliding in that area, so since you are having a problem, you need to concentrate on that area and try not to do whatever it is that is causing that callus to form.
I happen to think calluses that don't cause pain are good for us in that they protect our more sensitive skin below. I have really thick skin around my three middle toes on both feet, I believe because I have such long toes, that I scrape them on my lift as I run. They don't bother me at all. In fact, I wish the rest of my forefoot skin was as thick. I understand that thickened skin over a large area is good callusing, while thickened skin over a small, concentrated area could cause trouble. For me, the thickened skin or callusing around my toes protects me and doesn't cause me any pain, so I'm not going to mess with them, meaning I don't sand or trim my toes. Now isn't this like gross, or what?! ;-)
