#scrap mastery

[dailymtgflavortext]

"Where a lesser mind sees junk, I see infinite potential." 

-Scrap Mastery

[art-of-mtg]

Scrap Mastery (Commander 2014) - Dan Scott

[magicjudge]

if i control a mycosynth lattice, and i say have 10 lands in my graveyard, i then cast scrap mastery, the lands will return to play right?

No, this doesn’t work.

Mycosynth Lattice makes cards in zones other than the battlefield colorless, but it doesn’t make them artifacts. Only permanents on the battlefield get to become artifacts through the power of mycosynth.

So, when Scrap Mastery resolves here, each player will exile all actual artifact cards from their graveyard, then sacrifice all of their permanents, then return the exiled cards to the battlefield.