Contemplation on the filthy nature of the body-
Sixth Anuprekṣā (4) (contemplative meditation);
reflecting upon the truth that the body is a storage of filthy things like blood, stool, urine, phlegm etc.
aśuci khalvidaṃ śarīramiti cintayet... nirviṇṇaśca śarīaprahāṇāya ghaṭata iti aśucitvānuprekṣā.
(TaBhā 9.7)