What happened to the remains of all the ancient dead warriors?

If ancient battles are anything like Hollywood depict it with hundreds to thousands of warriors squaring of on the field of battle then charging at each other in a mêlée of horses, battle axes, swords and arrows. When the fighting is over there are sure to be hundreds or thousands of dead and dying. Where the winners might take the time to strip the dead of their usable gear they didn’t have heavy machinery as to dig large trenches for mass graves or man power and trees in many areas to round up all the dead and burn them, so what happens to the carcass of those unlucky to be slain? Where they left out there for the vermin to feast off of? If they were close to the land they lived in was it up to relatives to go out and find them to give them a proper burial? Did the winning side have special “clean up” crews that would go out there with large wagons and stack the dead in like cord wood to take to the funeral pyres?