I can provide some examples from the medieval Middle East that suggest that battlefield clearance was probably not a priority, especially for victorious combatants.

The Byzantine historian, Leo the Deacon, wrote in the 990s and twice records piles of bones left on the field of battle for long periods of time after an engagement had finished.

In 917, the Byzantines suffered a heavy defeat at the hands of the Bulgars, and were cut down in their thousands when they routed. Leo reports that 'even now there could be seen piles of bones at Achelous, where the fleeing army of the Romans was disgracefully slain.' While Byzantium was once again as war with the Bulgars at Leo's time of writing, there had been a prolonged period of peace where it would have been possible to clear the bones at Achelous. It may be argued that the Byzantines had little desire to reclaim the unrecognisable bones of men who had been 'disgracefully slain.'

Leo also reports that 'piles of human bones can still be seen to this day in many places there' when referring to the battlefield of Andrassos. In 960, a Byzantine army had trapped an army of the Hamdanid Emirate in the Tauros Mountains and severely mauled it, and decades afterwards the bones of many in the defeated Arab army clearly still lay there. We can guess that the Byzantines would have had little desire to clear away such a good warning against marauding Arab armies.

Slightly later, Byzantine princess/historian Anna Komnene reported that, during the First Crusade in the 11th century, the Turks left a 'mountain' of bones after a massacre of crusaders. Like the Andrassos example, it is possible that the bodies of defeated combatants were purposely not cleared in order to act as a deterrent against any future invaders.

You might be interested in two of our past threads, though they don't directly answer the question:

• In pre-modern warfare, how did opposing armies handle battle field casualties in multi-day engagements?: No flaired answers and focuses chiefly on the Early Modern Period and the American Civil War.

• What were the logistics of dealing with casualties in ancient and medieval battles? And how accurate are the Total War games?: Again, no flaired answers, and the reason it is rather low-quality is because it's a very old thread (three years old).