Master's Guide-Mural // Master's Manufactory

You may exile tokens you control as part of the materials required. However, because they aren't cards and won't stay in exile, any abilities that refer to what you "used to craft" the back faces won't refer to anything.

If a card that isn't a transforming double-faced card becomes a copy of a card with craft, it'll stay in exile if you activate the craft ability. It won't return to the battlefield.

The ability of Master's Manufactory can be activated no matter what happened to the artifact after it entered under your control. It may have left the battlefield, stopped being an artifact, or another player may have gained control of it.