Almost nil...? Sorry, not good enough.

Just because other sites tout it's effectiveness and claims of it being a 'residual' ammount of poison, it's a poison. How much of that poison will your body store, before reaching a toxic and irreversable level? And about smoking the vapors from that poison...does it make the compound safer or more toxic?

Being as how this is a medical cannabis site, and there are many folks here that even though it's a small ammount of poison, it could and would interract with some meds or medical conditions, and it's not worth the risk of injury or worse to a loved-one.

There are much safer alternatives for femming seeds. Light poisoning or aspirin treatments, for instance.