I received the following:
What is/are the proper way/s to dispose of Sacred Chrism. Is it only to be burned or, like many other things, can it be buried and thus "returned" to the earth?
The very best way would be to burn it.
It would be a wonderful thing to burn it in an olive oil based lamp, perhaps used as a presence lamp.
Otherwise, it is would be impossibel to burn it in a dignified way, I suppose it would also be possible to pour it into the ground, though I think I would put my effort into finding a way to burn it.
Perhaps there is a cathedral sacristan reading with experience of dealing with large quantities of sacred oils who can chime in.