Leaves and shoots, chopped in salads, but pungent. Use sparingly. The roots, early in the spring, can be eaten raw. The flowers too, can be eaten, but apparently palatability can vary.
It's called that in part because of the look of the flower, with all flowering bodies on one side mimicking the look of a scrub brush, but also apparently because a tea made from this plant will clear out your system.
The Musk Mallow is edible. The leaves, flowers, and seeds are all edible and mild. It grows pretty wild on our property in many places within our field.