The computer simulation of complex phenomena is a challenging issue for studying their properties. Several models and techniques have been developed in order to provide useful conceptual and computational frameworks. The aim of this paper is to present a simulation model based on the Reaction-Diffusion Machine (RDM) and to discuss its implementation by a system based on multiagent and Object Oriented paradigms. The chemical extraction of substances in washing phenomena occurring in percolation processes has been considered as reference application.