Ill-fitting toeboxes can rub against the foot, causing blisters, and eventually calluses and corns. Corns and calluses are easier to prevent than to treat. Corns and calluses generally need treatment only if they cause problems. Calluses and corns may heal by themselves eventually, once the irritation is consistently avoided. Corns and calluses are very common and do not look pleasant. As such it is used to treat warts, calluses, psoriasis, dandruff, acne, ringworm, and ichthyosis. Plant callus (plural "calluses" or "calli") is a growing mass of unorganized plant parenchyma cells. Such injuries are often no worse than torn calluses, cuts, burns and bruises. Friable calluses fall apart easily, and can be used to generate cell suspension cultures. Also, the corpse's feet had a lot of calluses. His voice began to give out, and he developed calluses on his vocal cords. "This game is absolutely guaranteed to put calluses on your trigger-finger", "InfoWorld" stated.