While cotton pads and cotton rounds can be used interchangeably, cotton balls are a different product. They can be used for pretty much the same things in salons and spas, but are generally more absorbent than pads and tend to fall apart easily, leaving traces of cotton behind. As they soak up more product, cotton balls are best at removing glitter nail polish. They can also be saturated with essential oils and used in a DIY aromatherapy diffuser.