Matsya Purana 227.76

227.76

dharmopadeśaṃ śūdrastu dvijānāmabhikurvataḥ.
taptamāsecayet tailaṃ vaktre śrotre ca pārthivaḥ .. 227.75 ..

A Śûdra who teaches Dharma to the twice born should also be punished by a sovereign by getting hot oil poured into his ears and mouth—75

A Brâhmaṇa who indulges with a Châṇḍâla woman or a woman of a different caste or eats their food or accepts a gift from them unknowingly tolas of gold or silver according to the seriousness of the offence The one who breaks anyone's bone should be exiled from the country—87