Air carrier Captain reported two DG pallets were removed during preflight after discovering the pallets were improperly built; with concern for one of the pallets having a leak.

Narrative

During Accessible Dangerous Goods (ADG) inspection; the FO found pallet 2R and 2L to be excessively wrapped in plastic making it difficult to verify labels and separation. Additionally; the boxes in the middle of the pallet were placed such that no labels were visible. There were some language barrier issues trying to convey the concerns so I intervened and got the Ramp Agent to help translate between the FO and the DG Agent. Pallet 2R plastic was opened to loosen the pallet enough to verify labels that were not visible. When the plastic on 2L was opened; there was a strong acrid odor from inside. Verification was stopped at that point and the pallet was requested to be removed. A discussion with the Supervisor was had prior to removal to see if we needed to wait for the pallet to be re-built but once there was concern of a leak; I made the decision to have the pallet removed with Supervisor concurrence and depart for the destination. Building the pallets without ensuring the labels are visible seems to be a repeat issue at this location.Cause: Pallet was built improperly not allowing for visibility of DG labels. Contributing factors may be associated with being new to the ADG pallet build requirements. Unsure about acrid odor or what caused that.Suggestions: More training of ADG build requirements with oversight from the trainer.