I believe (and someone correct me if I’m wrong, it’s been a while since I’ve taken biochemistry) hull cleaner is usually made of phosphoric or citric acid, and it has a higher affinity to binding to the milk’s (hydrogen?) molecules than the receptors it would bind to in your body to poison you. So the acid’ll bind to the milk and create some sort of solid (milk curdle) that will take longer for your body to digest, giving you time to call poison control.
Similar principle to drinking vodka if you’ve ingested methanol, but for that mechanism I believe vodka binds to the receptors in your body faster than methanol, and that’s what slows down the poisoning.
I don’t think I said anything mean or derogatory towards you, just that Ghibli being regard as “anime movies” is strange, and that you might be dismissing something being recommended before really knowing what it was about. Apologies for any offence, though.