An exclusive metablast you can use to manipulate objects. You have your usual dexterity (with range penalties), and can do anything you could do by hand or with simple tools like a rope, mallet, wrench, or screwdriver. You can create small amounts of substance to mend, seal or tie something up, which is then about as durable as a mundane object would be.
An exclusive metablast has none of the normal effects of that blast, including any other metablasts that would ordinarily apply. In effect, an exclusive metablast is a separate effect that replaces what the blast normally does. Still, it takes it's appearance from the blast it is used with, if it does any damage it is of the same type, and a Damage Imunity that would protect against the blast also protects against the exclusive metablast.
If you can only use the blast schtick to manipulate, and thus cannot do damage with it, this metablast schtick is free.