This invention provides compositions that are useful for polymerizing at least one monomer to produce a polymer. This invention also provides compositions that are useful for polymerizing at least one monomer to produce a polymer, wherein said composition comprises a post-contacted organometal compound, a post-contacted organoaluminum compound, and a post-contacted treated solid oxide compound. The post-contacted organometal compound includes metallocenes. The post-contacted treated solid oxide compound contains fluorine, boron, and a solid oxide compound.