From Terraria Wiki
Sold by the Steampunker (depending on the biome she's in):
- Green Solution when no other solution is being sold. Spreads the purity. In addition to turning all dirt-based biomes into normal grass biomes, spraying it onto Mushroom Biome grass will change it into Jungle biome.
- Purple Solution during a Blood Moon or Solar Eclipse if the world has Corruption. Replaces all dirt-based biomes with Corruption.
- Red Solution during a Blood Moon or Solar Eclipse if the world has Crimson. Replaces all dirt-based biomes with Crimson.
- Blue Solution when in the Hallow. Replaces all dirt-based biomes with Hallow.
Sold by the Truffle:
- When using the Purple, Red, or Blue solutions, Mud will be replaced with Dirt along the surface to accommodate grass blocks.
- There isn't a solution for the jungle biome, so keep that in mind when replacing it with glowing mushroom