My mother have freckles on her entire both arms. what over-the-counter product she can buy to remove them? she had them for many years.

None: True Freckles can not be removed with over the counter medications.

Freckles: There is no OTC product that will removes freckles which are sign of sun damage. She needs to have a dermatologist check her for skin cancer before worrying about removal. Ultimately, life similar to sun damage is cumulative and after a life of unprotected sun exposure, you cannot erase the damage with a cream. Please see your dermatologist. always use sun protection even in winter and cloudy days

Save your money: You are going to be disappointed. If there is a significant issue, see a dermatologist.