One other option for recovery of FCC feedstock from the VDU bottoms is to use a solvent extraction scheme, which may use liquid C3, C4 or C5/C6 as the solvent. Licensed processes are the Kerr McGee ROSE and DEMEX from UOP. Up to half of the VDU bottoms may be typically recovered, and % recovery depends on the metals and asphaltene content in the VDU bottoms. The ROSE license was bought over from Kerr McGee by KBR in 1995.