Musannaf Ibn Abi Shayba 1:476

476. Al-Fadl ibn Dukayn narrated to us, from Isra’il, from Jabir, from Salim, al-Qasim, ‘Amir, and Tawus: I said, "Should I perform ghusl (ritual washing) after cupping?" They said, "No." Abu Ja’far said, "Wash the trace of the cupping cups."