Air carrier Captain reported the transport of prohibited Hazmat cargo due to improper labeling of Hazmat cargo.

Narrative

During loading at ZZZ; I noticed about 17 electric chainsaws; battery operated that had a shiny label on them that said 'Lithium batteries forbidden for transport aboard aircraft and vessel'. I requested the presence of a hazmat person; and we both looked carefully over the packages for any UN number; but we could not find any. The decision was subsequently made to transport them to ZZZ1.Once we arrived at the destination; ZZZ1; the station manager; noticed the hidden UN3481 Class 9 label in the now bright sunlight; and said something like; 'Hey; this is hazmat!' At that point I had not even mentioned any of the confusion to anyone at ZZZ1. He discovered it on his own.The shipper used the aforementioned plastic label to hide what is probably a no longer used UN3481 Class 9 hazmat label relative to lithium batteries. Due to lighting conditions at the loading location at ZZZ; none of us ever saw that UN3481 Class 9 label under the other label.Upon the above discovery of the UN3481 Class 9 hidden label; I attempted calling the same above mentioned hazmat person at ZZZ (unable to reach); followed by a call to Dispatch with this information.1. For MYSELF; I know I need to be more vigilant and willing to bump ANY questionable aircraft cargo content. We can be the armchair quarterback later over it; and thereby put safety #1.2. Personnel used by the SHIPPER should be trained to proper standards regarding what items they are shipping (lithium batteries IN PARTICULAR).3. ALL of us need to be more vigilant in our hazmat handling duties and thought processes.4. There were numerous points that this load of chainsaws could ( and should ) have been detected and rejected.