Those grey ingredients you speak of were old legendary crafting materials used in the game. You use to have to farm specific areas in the open world to get them. People hated this and they took up too much space in the stash so the 20-30 legendary crafting mats were made redundant (you can sell them for gold from vendors thus the description).
The cube menu option Extract Legendary Power shows the old unique crafting items have been greyed out, my death's breath is in color, and it tells me to select a legendary item. Any item i click produces the error "you lack the necessary core incredients."
I have the grey ingredients in my inventory and stash, but they do not register in the menus for either the Cube or the Blacksmith. The descriptions themselves indicate they were used in previous versions of the game and only have value to vendors.
Unless I am missing something, I can neither use the blacksmith or kanai cube to create level 70 gear. Anyone know what I am doing wrong?
Later, the devs introduced new crafting materials that you gain from bounty caches. You get a stack of specific ones from each Act's cache. These are NOT the same as the original legendary crafting mats you have despite some of the artwork being recycled.
Just sell all the ones you have and then do a full set of bounties for all acts. You'll have a bunch of the legendary mats needed for extracting items to the cube then.