A friend asked me about Sweet Gumballs. I figured I'd share this here in case it helps someone else:
If the sweet gumballs are not in season, you can use the leaves, stems, and inner bark to extract the antiviral properties. I learned that by listening to and taking notes from the old Tommy Bass videos. The gumballs have higher amounts of storax, but there is a moderate amount in the leaves, stems, and bark. Just use a higher herb-to-solvent ratio. The same is true with a lot of herbs. For example, higher amounts of resveratrol (antiviral) are in grape skins, but you can also get it from the leaves.