Leviticus 1:16

1:16 Then the priest must remove its entrails by cutting off its tail feathers, and throw them to the east side of the altar into the place of fatty ashes,

Leviticus 4:12

4:12 all the rest of the bull – he must bring outside the camp to a ceremonially clean place, to the fatty ash pile, and he must burn it on a wood fire; it must be burned on the fatty ash pile.

Leviticus 6:11

6:11 Then he must take off his clothes and put on other clothes, and he must bring the fatty ashes outside the camp to a ceremonially clean place,