The invention presented involves a method for regenerating, replacing or treating the catalyst in a hydroprocessing reactor, the method comprising admixing with the feedstock, recycle stream or hydrogen stream of the reactor an additive which comprises a nonionic, organometallic platinum group metal coordination composition which is a) resistant to breakdown under ambient temperatures; b) capable of breakdown at temperatures existing in the vicinity of the catalyst; and c) does not contain a disadvantageous amount of phosphorus, arsenic, sulfur, antimony or halides.