Currently there's no way for World Creators to clear PlayerData keys, we can set the value to whatever is the smallest, but the key is still going to exist forever, take space, and be synced to every other player unless the user manually resets his player data.

If a complex world goes through rapid changes or frequent updates to their systems that involve PlayerData there's a big chance some keys will turn obsolete, and it is likely that recurring visitors will unavoidably store unused keys and data, unnecessarily cluttering the network and their persistence data.

An Udon method for PlayerData.Remove(VRCPlayerApi player, string key) would allow for creators to manually handle clearing these keys.

I think there should also be another option for creators that are not familiar with Udon and mainly rely on prefabs.

Example scenario: using a badly coded prefab or too many prefabs that fill up the PlayerData size. Even if the prefab is deleted, a new player with no PlayerData would not experience issues, but a recurring player might because he still has the old keys.