A couple of things :
1. It's water soluble obviously as you chuck it in the pool, but I don't know if it'll mix with oil.
2. If it *is* soluble, you'd probably have trouble with the viscosity of the stuff you're trying to filter, restricting it's ability of the floc to clump particles together.
Has anyone thought of an air-bubbler arrangement for filtering out chunkier particles? Without going too much into the finer details, surface tension on the surface of tiny bubbles should make particles cling to them (similar to pepper on water) and float up where they can be skimmed off. Something like a aquarium pump and a few stones in a container, run for 10 minutes, might do something.
It might do nothing too, just trying to apply a design I've seen in various industrial plants for particle separation