How would you dispose prep-n-etch
I've have a few thoughts and from searches I've done. First, phosphoric acid is in fertilizer so it should be ok to just dump it. I did on a patch of weeds and it didn't phase them a bit! Another thing is this stuff is also in soft drinks! (on a smaller scale of course)
Then I think of what Prep-n-etch is actually sold for which is to etch concrete. You would pour this on your concrete and after a set time, rinse it off. If it was really bad for the environment, I think there would be all kinds of warnings, etc about doing that. Nobody is going to collect the run off so into the ground it would go.
Lastly, the amount us car guys would dump isn't much. Not like we're a big factory or anything.
One thing to remember too is that this stuff lasts and lasts and lasts! In fact, other than getting kind of gunky after many uses, it still keeps right on eating rust! It's unbelievable. When I tried vinegar it worked great the first time but the second time it's performance dropped big time. Then there's that smell...