The water in which a person has dipped their hands or feet is only used for what has dripped from the limbs or touched the body, and it is considered little compared to the rest of the water. Therefore, it is permissible to perform ablution and bathing with it; because the water that has mixed with used water is judged by the predominance of weight, and here the used water is little compared to the rest of the water. Refer to: Maraqi al-Falah, pp. 26-27, and the commentary of al-Tahawi on Maraqi, pp. 19-20, and Badai al-Sanai, 1/16, and al-Ikhtiyar, 1/20, and al-Lubab, 1/18-19, and al-Hadiyya al-Alaiyya, pp. 39-40.