It’s time to explore the world of sound! What kind of sound do you want your shaker to make?
Piano / Soft: use Polenta or Sand for a soft and gentle shaker!
Mezzo Piano / Sharp: use Rice for a sound that is more pointy!
Mezzo Forte / Medium Loud: use Lentils or Corn for a rough and loud shaker!
Forte / Loud : use Beans for a harsh, loud rattling sound similar to maracas!
Source: http://www.wikihow.com/Make-an-Egg-Shaker