The Compendium of Caraka 6.7.85

6.7.85

citrakamelāṃ &bimbīṃ vṛṣakaṃ trivṛdarkanāgarakam/
cūrṇīkṛtamaṣṭāhaṃ bhāvayitavyaṃ palāśasya//
&`nimbaṃ' iti pā-.
kṣāreṇa gavāṃ mūtrasrutena tenāsya maṇḍalānyāśu/
bhidyante vilayanti ca liptānyarkābhitaptāni//

Citraka, elā, bimbī, vṛṣaka, trivṛt, arka, and nāgara / powdered together should be impregnated for eight days with the alkali of palāśa / strained through cow's urine. By this, his round patches quickly / break open and melt away when smeared and heated by the sun.