Can you use dog liquid tartar removal as mouthwash for a human? i imagine if it won't kill a dog it should be ok.

Hmmmm: Dogs eat raw chicken, dirt and mud, bunny feces etc. And don't generally get sick. I hope you are not thinking of trying those things as well. There are better ways to keep your teeth free of tartar. Your dentist can help you decide how to go about that.

Chocolate: Large amounts of chocolate can kill your dog, but based on your reasoning, humans would also succumb to "death by chocolate". May I suggest you see a dentist to have your calculus removed.