From Monkey Island wiki
Ash-2-Life is a voodoo powder (formerly a cream) capable of bringing the dead temporarily back to life.
In Monkey Island 2: LeChuck's Revenge, Guybrush gets some of this powder from the Voodoo Lady and uses it to bring Rapp Scallion back to life. The powder requires some of the remains or ashes of the deceased mixed into its recipe in order to work. A jar of an older version of the product is on display at the International House of Mojo in the Scabb Island swamp.