Crush whole grapes on a flat surface, using the back of the spoon. Separate the seeds from the pulp and skin on the grapes, and scoop them into a strainer. Run water through the strainer to clean off as much pulp as possible.
Pour the seeds into a container, fill the container with water and put the lid on loosely. Place the container in a spot that doesn't get direct sunlight and leave it for 2 to 3 days.
Pour the water out of the container. That water will contain excess fruit pulp, skin and leftover leaves. It may also contain seeds that were not viable and floated to the top. Add new water, stir and pour out again. Repeat with one more rinse.
Pour the seeds out on a coffee filter and set them in a place that gets full sun, but is protected from wind and birds. Leave them until they're dry; this process can take up to one week.
Crush dried grape seeds on a hard, level surface, using the back of a spoon or other hard tool such as a clean hammer. This grape seed "extract" can be added to yogurt, ice cream, smoothies, etc.