The Alabaster Pot of Remembrance is a pot presumably made of alabaster (hence its name) which holds special clay designed to reverse the effects of memory loss (specifically from excessive use of the Fluttering Finger Mindslip technique). It was held down in the Cave of Mysteries at the end of the Corridor of Unbelievable Agony before it was shattered in battle in the Kung Fu Panda: Legends of Awesomeness episode "Fluttering Finger Mindslip".
The Pot of Remembrance is a gray pot full of a brownish-gray clay. The clay seems to be infinite, since the contents of the pot were disturbed several times during Po's battle against the memory-lossed Furious Five, only to remain completely unexhausted in the end.
In "Fluttering Finger Mindslip," Po excessively used a kung fu technique that caused memory loss on the Furious Five with disastrous results. He was forced to reveal to Shifu what had happened. After further reading the scroll detailing the technique, they learned of the Alabaster Pot of Remembrance and its abilities.
Traveling down to the Corridor of Unbelievable Agony where the pot was kept, Shifu tasked Po with retrieving it while Shifu searched for the Furious Five to keep them out of trouble. Despite several mishaps with the various traps and keys involved, Po was able to successfully obtain the pot. He brought it back to the Hall of Warriors and found Shifu battling the Five, who had been manipulated by Taotie into believing that Shifu and Po were their enemies. In the battle that followed, Po was able to successfully cover the Five's heads with the clay one by one. The clay quickly hardened as the memory loss was "drawn" out of them, and cracked and fell off once the process was complete.