(1) Threshing: Threshing is separation of grains from chaff. It can be done using any one method out the three i.e. (a) manual (b) with the help of Animals and (c) using machines.
(2) Winnowing: Winnowing is a method to separate heavier and lighter components of a mixture by wind or by blowing air.
Winnowing is an agricultural method for separating grains from chaff. It is also used to remove hay and chaff or other pests from stored grains.
(3) Sieving: It is a method to separate larger substances from smaller substances using a sieve. It is very easy and cheap method of separation. Components of same sizes in a mixture cannot be separated. For example, you cannot separate chalk powder from flour.