Some complex algorithms have been constructed and successfully applied to the GRBM/BeppoSAX 1 s ratemeters, in order to identify the true cosmic GRBs on other celestial transient events, both triggered and not by the on-board logic. These algorithms turned out to be very effective to distinguish GRBs from other transient events, like solar hard X-ray flares or phosphorescence spikes due to high-energy particles. The most effective condition was the hardness ratio threshold: this is based on the well known spectral hardness typical of GRBs. These algorithms have been used for two kinds of GRB quest: on- and off-line searches.