Ad hoc networks are distributed, self-organized wireless networks. By their nature, it is easy for a malicious user to enter this kind of networks with the intention of disturbing the way they are behaving by not participating to the network. This kind of behavior is a form of selfishness where nodes want to save their energy by not routing packets. Many solutions based on virtual currency mechanisms or on reputation mechanisms have been shown to increase the networks reliability for this kind of problems. We advocate in this paper that this issue can be treated with local algorithms that have minor drawbacks compared to sophisticated solutions developed in other works. We conduct an evaluation of our solution, which shows satisfying enough results to be used in civilian spontaneous networks.