Separating Solid from Solid

Handpicking 

This method is used when :-

• Larger sized impurities need to be removed eg. rocks, pieces of dirt, husk from rice, wheat or pulses etc.
• The quantity of impurities is not large.

Threshing:

• Threshing is the method used to separate grains from stalks etc.
• Stalks are beaten to free the grain seeds.
• Machines are used to thresh large quantities of grain but for smaller quantities, bullock carts are used.

Winnowing:

• Winnowing is used to separate heavier and lighter components by wind or by blowing air.
• It can be used to separate grain from husk or a mixture of dry sand with saw dust and dried leaves.
• The husk particles are carried away by wind and the grains are collected below.
• This husk is used for other purposes like feeding fodder .

Sieving:

• It separates material s on the basis of their. 
• Smaller components are able to pass through the sieve whereas bigger ones are not.
• Eg. removing husk and stone from wheat in flour mills.