What characteristics indicate that a nail polish has gone bad?

A nail polish that has gone bad often displays certain signs that indicate its usability has diminished. One of the key characteristics is a change in its consistency. When nail polish becomes thick or exhibits separation of ingredients, it suggests that the formula has deteriorated over time. This thickening can make application difficult, leading to uneven coverage and a less desirable appearance on the nails.

Additionally, the separation of ingredients indicates that the components that normally keep the polish uniform have broken down, affecting its performance. This change is generally due to the evaporation of solvent or the degradation of other components in the formulation, which typically occurs with age or exposure to air.

While an unusual smell or a strong odor might also suggest that a product is not at its best, the physical characteristics of thickness and separation provide a more direct indication of a polish that has likely gone bad and should be discarded for optimal results during use.