I'm designing a brute force mage and intend to use Spirits of Man to siege Wards.

Is the Shattershield spell the only way to do this or is there another more general-purpose spell that can break one down?

All you need is a Mana-based spell (so you can cast on the Astral) that does physical damage (so you can damage the ward). Manabolt or Death Touch both work. Shattershield is awesome for mages because of the -3 drain, but lame for spirits. I'd go with manabolt, the Ha-du-ken.

Well...you could enchant a monofilament chainsaw as a weapon focus.

Do you want to destroy wards or are do you just want to not have to worry about them?

p.186
Magic + Charisma vs Ward's Force x2 to push through

A harder way, though the summoner will not be informed is to fake his signature with the flexible signature metamagic after tracking him from the ward with astral tracking.

You can attack a ward (book says astral mana barrier, but lets just assume that they meant the same thing) in Astral combat, same as you would attack any barrier, and since it has an astral form, Im pretty sure direct Mana combat spells work. Someone may correct me on that.

My idea is to have Spirits of Man destroy Wards via Innate Spell all over a compound so the security mage doesnt know which ward the main assaulting force is entering through. It should also prevent low charisma teammates from risking disruption.

My brute force mage is an elf with high CHA so emulating aura's is possible but for a high risk op I just wanna pop the ward and let spirits runneth-over through the breach.

Great pointers everyone!