Initially, copper is oxidized to the cuprous ion:
(1) Cu → Cu + e
The cuprous ion reacts with the chloride ion to form the insoluble white colored salt cuprous chloride:
(2) Cu + Cl → CuCl
The cuprous chloride reacts with atmospheric moisture and oxygen to form a green cupric chloride/cupric hydroxide compound and hydrochloric acid:
(3) 4 CuCl + 4 HO + O → CuCl·3 Cu(OH) + 2 HCl
The remaining copper is oxidised by air to the cuprous ion:
(4) Cu → Cu + e
The cuprous ion reacts with the chloride ion in the hydrochloric acid to form the insoluble white colored salt cuprous chloride:
(5) Cu + Cl → CuCl
The reaction then repeats from equation (3). It is the presence of two different white and green salts that lead to the fuzzy green appearance.