Always toast your spices. Toasting releases the natural oils of the spices and sanitizes them. As Lior pointed out, you never know how many hands touched the spices before they made it to your jar. The easiest way to toast spices is by placing them on a sauté pan over medium heat. Flip the spices occasionally until they become fragrant, a sign that they are fully toasted. Then immediately remove them from the heat.
Toasting Until Fragrant