This involves removing the outer cover, including the husk, bran and germ.
VOA: special.2010.06.30
For example,cinnamon comes from the hard outer cover of cinnamon plants.
VOA: special.2009.05.19
The sediment layer would have to be less than a km (half a mile) thick in order to have the observed effect, and would probably cover only patches of the outer core.
The outer body of the EX-G1 is made from stainless steel to withstand external shocks while a polycarbonate cover absorbs shocks to the body side near the shutter.