I believe there are certain substances on or in pollen that function to make it useful/active to a pistil, and I would not desire to rinse any of those factors out by using liquid solvents. Therefore I would investigate the use of gaseous killing agents. Perhaps pure CO2 or nitrogen gas for a week would kill pollen, leaving all enzymes and sugars intact. You would want to use a control female plant to test for actual killed pollen, the desired result on this plant being no seed formed.

That sounds reasonable. I'd read in various journals about the alcohol and freezing methods, just not how they work. Anyone else?

did you have any luck?