You can use the following methods to treat gray nails: soak the nails with warm water, soak time according to the thickness of the nails until the nails are soft, remove the nails with a nail clipper, and then soak the nails with ten percent glacial acetic acid for a quarter of an hour, three times a day, for a week. If not cured, you can follow the above method and then treat 1 course of treatment. You can use topical medications such as naphthol ketoconazole cream or compound clotrimazole cream, etc. You can also consider using internal medications such as mycophenolate or itraconazole capsules.