You can eat them in stir fry when they are green and young. We haven't tried that yet. We allowed ours to dry and turn brown. Then we gave them a good shake to harvest all the seeds. That was super fun and made a neat sound. Once most of the seeds were out we soaked the dried luffa in water for about 45 minutes. Below you can see Haden easily peeling off the out layer. Once that is gone we laid them in the sun to dry.
They work great for scrubbing both your body and your dishes. I can't wait to include them in little gift baskets with some homemade soap. We are loving the low maintenance, useful luffa plant.