To suspend temporarily the duty on a mixture of 2-Naphthalenesulfonic acid, 6-amino-5-[[2-[(cyclohexylmethylamino)sulfonyl]phenyl]azo]-4 -hydroxy-, monosodium salt, 2-Naphthalenesulfonic acid, 6-amino-5-[[4-chloro-2-(trifluoromethy)phenyl]azo]-4-hydroxy -, monosodium salt, and 2-Naphthalenesulfonic acid, 6-amino-4-hydroxy-5-[[2-(trifluoromethyl)phenyl]azo]-, monosodium salt.