僧羯磨 2.137

2.137

不還物法（於僧中捨衣竟，不還者，突吉羅。若作淨施、若遣與人、若持作三衣、若作波利迦羅衣、若故壞、若燒、若作非衣、若數數著壞，盡突吉羅。）

The rule on not returning the items: (When the robes have been forfeited within the saṃgha, if one does not return them, it is a duṣkṛta. If one makes a pure donation of them, or sends them to give to someone else, or takes them to make the three robes, or makes a parikāra robe, or intentionally damages them, or burns them, or turns them into non-robes, or repeatedly wears and wears them out, all are duṣkṛtas.)