You live in California....i would think one call to the repair guys and they would be out there fixing this drain for you, after all, one call to the EPA would probably shut them down....of course they might declare your property an eco-disaster zone or something....
In all seriousness, i've no idea how you could dissolve it, or even if it really clogged up your drain.
If i were to try anything a bottle of DAWN dishwashing detergent is what i would try, that's what the clean up oil spill covered animals with.