Whether the laser can remove melanin depends entirely on what kind of disease is causing the melanosis. In the case of nevus of Ota, freckles, hyperkeratosis, blue-black tattoos, brownish nevus of the cheek area and coffee spots then laser treatment is an option. Laser treatment of melasma needs to be done very carefully.
If the hyperpigmentation is caused by medication-induced inflammation or caused by internal disease, laser treatment is not suitable in most cases.