Dream Solvent is a new resource that was added to Genshin Impact in Update 1.5. It has been added to the loot pools of all world bosses, at all difficulty levels, so will be available to all players regardless of their level.
The Dream Solvent is able to chance character level-up materials into a new type of material, cutting down on the need to endlessly farm specific types of resources and materials if you already have some available in a different element.
For example, by visiting the Alchemy table and going into the Conversion menu, players will be able to see all their character level-up materials. If the player had a Dvalin’s Plume, and instead wanted a Dvalin’s Claw, they would be able to spend one Plume and one Dream Solvent to convert the item into one Claw.
This is extremely useful as the top-tier talent materials can be very difficult to farm, so being able to alter the types like that is hugely beneficial for players. You will need one Dream Solvent for every item that you wish to change, so there is something of a cap on how many times it can be done, just due to the limited number of times you can farm world bosses each week and expect to get rewards.