James McMurray
First Post
Wow. You'd almost think the original post hadn't specifically mentioned not wanting RP reasons for not summoning a solar. 
As for fighting a Solar, there have been several good suggestions:
Gate another creature of your own
Maze
ForceCage (especially if in a diemensionally locked area)
Blasphemy, Word of Chaos, or other no save banishers.
A few more include:
Wish it hadn't been summoned
Harm + quickened X spell
Keen vorpal swords in the hands of improved critical using
weapon masters with 3 levels of cleric (and the Asassin's
Senses spell from Relics and Rituals)
Create a gate and then bull rush him though it, ending the gate
afterwards (the Solar is now in hell, and likely won't be coming
back unless a long-term contrct was involved)
Slaracean dragons are mean (I've heard)
Hope this helps. My party is soon to be cresting into 17th level range. But in my game they're already afraid to summon monsters, much less Gate them in. I've yet to have a high-powered creature turn on them, but they know that no supreme entity of good is going to be at their beck and call without some kharmic backlash of some sort.

As for fighting a Solar, there have been several good suggestions:
Gate another creature of your own
Maze
ForceCage (especially if in a diemensionally locked area)
Blasphemy, Word of Chaos, or other no save banishers.
A few more include:
Wish it hadn't been summoned
Harm + quickened X spell
Keen vorpal swords in the hands of improved critical using
weapon masters with 3 levels of cleric (and the Asassin's
Senses spell from Relics and Rituals)
Create a gate and then bull rush him though it, ending the gate
afterwards (the Solar is now in hell, and likely won't be coming
back unless a long-term contrct was involved)
Slaracean dragons are mean (I've heard)
Hope this helps. My party is soon to be cresting into 17th level range. But in my game they're already afraid to summon monsters, much less Gate them in. I've yet to have a high-powered creature turn on them, but they know that no supreme entity of good is going to be at their beck and call without some kharmic backlash of some sort.