Internet Bad Neighborhoods have proven to be an innovative approach for fighting spam. They have also helped to understand how spammers are distributed on the Internet. In our previous works, the size of each bad neighborhood was fixed to a /24 subnetwork. In this paper, however, we investigate if it is feasible to aggregate Internet bad neighborhoods not only at /24, but to any network prefix. To do that, we propose two different aggregation strategies: fixed prefix and variable prefix. The motivation for doing that is to reduce the number of entries in the bad neighborhood list, thus reducing memory storage requirements for intrusion detection solutions. We also introduce two error measures that allow to quantify how much error was incurred by the aggregation process. An evaluation of both strategies was conducted by analyzing real world data in our aggregation prototype.