I say, and with God's success: Sweat is considered like the remnants of food; if the remnants are pure, then the sweat is pure: like camels, cows, sheep, and horses; because the remnants are mixed with saliva, and the ruling on saliva and sweat is the same; because both are generated from flesh. Refer to: Sharh Al-Wiqayah p. 103, and Umdat Al-Ri'ayah 1: 93, and God knows best.