Collected from a brackish water area. ~Driftwood Preparation~ Rinsing with water and brushing ↓ Soaking in fresh water for about 7 days ↓ Rinsing with water and brushing ↓ Drying This is amateur-level tannin removal. Thank you for your understanding. While I try to work carefully, there may be sand and dirt that I can't remove from the driftwood. Also, as it is a natural product, there may be cracks, scratches, and splits. If used underwater, such as in an aquarium, or with living organisms, please do so at your own risk. Please also perform a sinking treatment.