When a nail cracks or splits, nail glue or mending tape is your best solution. Dot the nail glue onto a piece of a tea bag, or coffee filter paper, and cover the nail where it is torn. File the nail smooth and cover it with polish if you like; this should last until you can get to the parlour. When a nail cracks or splits, nail glue or mending tape is your best solution. Dot the nail glue onto a piece of a tea bag, or coffee filter paper, and cover the nail where it is torn. File the nail smooth and cover it with polish if you like; this should last until you can get to the parlour.