Pet guinea pigs typically need their nails clipped regularly by their owners or veterinarians. Otherwise, the nails continue to grow and either break off or curl under painfully. Their nails wear down naturally only if they spend a lot of time on hard, rough surfaces such as brick or concrete.
While some guinea pigs owners like to engage an assistant to hold the pet steady, others just wrap the animal in a soft towel or blanket. With the animal's face covered and feet exposed, it lies on its back in the lap of the groomer. Human or animal nail clippers work equally well. Only the ends of the nails are trimmed. A nail should not be cut as far as the "quick" or tip of the toe, because it is easy to nick the flesh and cause bleeding. Quick that has been cut should be treated with a dab of hydrogen peroxide.