Garudapurana 1.69.36

1.69.36

mṛlliptamatsyapuṭamadhyagataṃ tu kṛtvā paścātpacettanu tataśca biḍālapuṭyā /
dugdhe tataḥ payasi taṃ vipacetsudhāyāṃ pakraṃ tato 'pi payasā śucicikraṇena //

Having placed [the pearl] inside a clay-smeared fish cavity, one should then cook it gently, and next in a cat's cavity; / then one should cook it in milk, [then] in nectar, and after cooking, with pure, glossy milk.