Banishment

Banishment is an abjuration spell that banishes outsiders to their home plane.

Effects
A banishment spell is a more powerful version of the dismissal spell. It enables you to force extraplanar creatures out of your home plane. Up to 2 HD of creatures per caster level can be banished. To target a creature, you must present at least one object or substance that it hates, fears, or otherwise opposes. For each such object or substance, you gain +1 on your caster level check to overcome the target's SR (if any) and +2 on the saving throw DC. For example, if this spell were cast on a demon that hated light and was vulnerable to holy water and iron weapons, you might use iron, holy water, and a torch in the spell. The three items would add +3 to your check to overcome the demon's SR and add +6 to the spell's DC.

At the DM's option, certain rare items might work twice as well (each providing +2 against SR and +4 on the spell's DC).