The capacity of an ad-hoc network is severely affected by interference between links, and several efforts to model this effect make use of 'clique' structures in the ad-hoc graphs. We propose a fully distributed heuristic algorithm to approximate cliques in such networks. We further propose methods to shrink the generated set of cliques to a set of maximal cliques. Simulation results verify the efficacy of the heuristic algorithms and also analyze their computation time.