This work introduces an alternative method for extracting calcareous microfossils from carbonate rocks using acetic and hydrochloric acids. The method, developed at the Laboratory of Micropaleontology, Dept. of Geology/Federal University of Rio de Janeiro (UFRJ), has proved to be efficient in separating carbonate tests through the application of acids with controlled reaction time. Compared to traditional methods, especially to hydrogen peroxide digestion, the best results show an almost eight-fold increase in the number of extracted microfossil tests. The time required for the procedure does not exceed 2 hours.