Fairy Dust

Sprinkle on kegs, furnaces, and other refining equipment to instantly receive their product.
Overview
Fairy Dust is a single-use craftable item that instantly completes the process currently being performed by a machine. The player receives the crafting recipe after completing the "The Pirate's Wife" quest for 
Fairy Dust can also be obtained from several other sources: the Prize Machine can award 1–2, Golden Fishing Treasure Chests have a 7% chance to contain it, and it is a reward from the Raccoon questline, giving 5 for the fourth request and 7 for the sixth request and beyond. The Bookseller trades 8 Fairy Dust for 1 Book Of Stars, and once unlocked, the Raccoon's wife near the Giant Stump trades 1 Fairy Dust for 1 Mystic Syrup.
When used on a machine, Fairy Dust finishes the current production instantly. It does not work on Incubators, Ostrich Incubators, or Slime Incubators. On casks, it advances the product by one quality tier per use rather than jumping directly to iridium quality unless the cask is already at gold quality; in that case, repeated uses can continue upgrading it until iridium quality is reached. Fairy Dust is not used in tailoring or dyeing.
Official description
Sprinkle on kegs, furnaces, and other refining equipment to instantly receive their product.