That's not a bad idea but with so much solution, I doubt that what little organic matter would be present, would diminish the bleach activity whatsoever. I don't know this and I do in fact pre-scrub my pots before putting them into the bleach solution. I just want to remove as much grim as possible so that the bleach solution works more quickly and more efficiently. I just rinse the pots in clear water after the bleach soak/scrub. I actually like having a tiny bit of residual bleach in the porous clay to at least temporarily prevent mold returning.
