Start by soaking them in a mixture of water and bleach for a few hours to eliminate any grime, salt, and fishy smell. If your seashells still have bits of seaweed or sand on them, soak them in a mixture of water and vinegar for about 30 minutes. Gently scrub with a soft brush to remove the residue. Rinse well and let them dry completely before using them in your crafts. This simple process ensures the shells are fresh and ready for your creative projects!