Starling 2 has automatic batching behind the scenes. So in general you no longer need to explicitly use batches, i.e. MeshBatch objects. You can just create a bunch of Meshes (or anything that is also a Mesh such as a Quad or Image), add them to a container such as Sprite, and let Starling take care of them.
You mostly need to take care that it can batch the Meshes you supply. This means ensuring they are drawn the same way, with e.g. the same texture, the same blend mode. Then Starling can batch them and it only needs one draw call to draw them. You can enable stats to see how many draw calls are required.
Do it this way and there is no need to reset everything; it keeps track of anything that changes (with a
setRequiresRedraw() call which you can call if you change something).