Ashtangasamgraha 21.30

21.30

kruddhaṃ malamalaṃ jetuṃ nālpabhāvādubhāvapi |

doṣā doṣātmakatvācca na same 'pi parasparam ||

kaṣāyaṃ taṃ parisrāvya nidadhyāttāmrabhājane ||

karṇarogapratiṣedhaḥ

Neither doṣa is able to conquer an enraged waste product owing to their own slightness; / nor, since they are of doṣic nature, can they conquer one another, even when equal.
Having strained that decoction, one should place it in a copper vessel.
Treatment of ear diseases.