Midrasch zu Schemot 29:32

35) (Vayikra 8:31): "And Moses said to Aaron and to his sons: Cook the flesh at the door of the tent of meeting," as it is written (Shemoth 29:32): "And Aaron and his sons shall eat the flesh of the ram and the bread that is in the basket, etc." And it is written (Shemoth 29:32): "And what is left over of the flesh and of the bread you shall burn with fire," whereby we are taught that what remains of the miluim is to be burnt.