Does pKreoss' Purification spell clear out Cloud Effects like Murder of Crows?
Murder of Crows is an upkeep spell, so it would be removed.

It would be removed if any part of the Murder of Crows AoE was within range of Purification.  Like with a model, something is within if any part of it is within.  If you used purification to take Arcane Shield off an Iron clad, you would only need to make sure the edge of the Ironclad's base was within the spell's effect.  It would be the same with any other "thing" that was getting dispelled.