Abstract : Object-Oriented Programming (OOP) is a pillar of actual, and most probably future, software engineering. Within the advances for OOP, Garbage Collection (GC) is one the major improvements that brought both large productivity and reliability benefits. Yet, to our knowledge, no widely used distributed systems benefit from a complete Distributed Garbage Collector (DGC) at this time. We believe that this situation is due, a least partly, to actual DGC performance issues. In this paper, we introduce the idea of sketch based DGC where object-graph fragments are sketched rather than explicitly represented. We prove, under reasonable assumptions that sketched messages are smaller up to one order of magnitude than their explicit counterparts. Those results apply to most of state-of-art DGC methods. In the case of the Veiga and Ferreira DGC algorithm, the improvement is more than a factor~4 under very limited assumptions.