Lighting the Sludge on fire with the EPC's Burning Nightmare mod is always a fun and creative way to clear swarms of bugs. In fact, if you fired a charged shot at the sludge with the Persistent Plasma overclock equipped, you can get 3 layers of slowdown and DoT that can take out even Bulk Detonators! You may have to repeat the process of laying out new Burning sludge/plasma 2-3 times for Bulks, but it works surprisingly well.