Place 1/2 cup sunflower seeds into a blender. Pulse the blender several times to break up the shells without destroying the fruits. Short two- or three-second bursts should be sufficient. Check the shells after each burst to ensure they are breaking up, but the fruits are largely intact.
Pour 2 inches of cold water into a bowl, and then add the broken shells and seeds to the water. Scoop up the floating shells with a spoon, and discard them.
Repeat Step 1 to break up more sunflower seed shells if you have them. Pour each batch into the water with your previous seeds, and scoop out the empty shells again. Continue until all shells have been removed.
Stir the seeds along the bottom of the bowl to bring any remaining shell pieces to the surface, and remove the pieces as they float up until only seeds remain in the water.
Hold a mesh strainer over the sink, and pour the water and seeds into it.
Spread out paper towels four to five layers thick on a plate. Pour the seeds out onto the paper towels, and spread them out as evenly as possible. Blot the surface of the seeds with another paper towel to draw up more water.
Look through the seeds, and pull out any remaining shells. The seeds can be used immediately if you are going to bake them. Let the seeds dry thoroughly before placing in a resealable plastic baggie to store for later.