On the topic of chemical, how do you know if something is dangerous -- in the context of household item? Even with the MSDS and/or knowledge of the compositions, layman doesn't really have any sense on how dangerous something is (as it's all missing dosage). I'm a bit on the paranoid side (mostly because I think my roommate/ housemate has always been too liberal with spraying chemicals crap everywhere), and most of the time, even if I wanted to I have no idea if I want to use something in my house.