Purifying beacons

[OmniJack]

How do you purify a beacon? I've beaten the game and my file says 100%, but the option to purify a beacon is still greyed out.

[Baba black bear]

talk to Fefeti who is located in the left room of the castle under the card copy shop to obtain fefeti's tears which is an item that allows you to purify the beacons.

However, I have yet to find anything useful with purifying the beacons other than removing the extra shield you would get instead when u heal at an upgraded one

[Arcanestomper]

You actually have to shard the beacon right next to him before he will mention purifying them.