
Hardeners or polishes containing formaldehyde should be avoided for their drying effect on nails. A waterproof coating is to be tried for sealing moisture in the nail and repelling water and dirt. A waxy lip balm can is best for moisturizing nails. Absence of a base coat underneath your regular polish causes yellowing of the nails. If it is nail fungus it needs cure. Discolored nails can be lightened with a whitening scrub containing a mild abrasive, or with a remover containing a lemon juice -like ingredient that bleaches out the yellow color.