Several software systems have been developed recently for the automated generation of combustion reactions kinetic mechanisms using different representations of species and reactions and different generation algorithms. In parallel, several software systems based on rewriting have been developed for the easy modeling and prototyping of systems using rules controlled by strategies. This paper presents our current experience in using the rewrite system {\sf ELAN} for prototyping the automatic generation of the combustion reactions mechanisms previously implemented in the {\sf EXGAS} kinetic mechanism generator system. We describe how to express in {\sf ELAN} acyclic and cyclic molecules, reactants, elementary reactions and the primary mechanism for acyclic species. Examples and generated outputs are given.