A method for removing cobalt values from the crude product of a cobalt-catalyzed hydroformylation reaction by the application of an airless cobalt demetalling step upstream of the stripping step of a Cobalt Flash hydroformylation catalyst recovery process for C.sub.4 to C.sub.14 olefins, whereby no oxygen is required to oxidize cobalt carbonyls to their cobaltous form. This airless demetalling step may also be used downstream of the stripping step in the case of C.sub.7 to C.sub.20 olefins to remove carbonyls from a water soluble cobaltous salt and carbon carbonyl stream which is taken as bottoms from the stripper reactor.