A method of re-using a spent fluid catalytic cracking (FCC) catalyst, previously used in an FCC process, in an additional FCC process, where the method includes the steps of: providing FCC catalyst that has been utilized in an FCC process, defined as spent FCC catalyst, wherein the spent FCC catalyst includes both aluminum and at least one rare earth element therein; and reacting the spent FCC catalyst with an extracting agent to extract at least a portion of the at least one rare earth element from the spent FCC catalyst, while extracting no more than half of the aluminum from the spent FCC catalyst. After performing the reacting step, the reacted spent FCC catalyst can be used in an additional FCC process.