How can I effectively revive sphagnum moss that has become dry and brittle?

To effectively revive dry and brittle sphagnum moss, you can soak it in water for a few hours to rehydrate it. Make sure the moss is fully saturated but not waterlogged. Then, place it in a humid environment with indirect sunlight to help it regain its moisture and vitality. Regular misting can also help keep the moss hydrated.