> that doesn't mean I want
> laboratory grade acid splashing on my skin or eyes.
Actually, pure phosphoric acid isn't even a liquid. But we weren't talking
about "laboratory grade acid" (whatever that means, most labs use mostly
dilute acids anyway). The solutions commonly sold to remove rust, are
already pretty dilute. I generally don't even bother with rubber gloves
when working with DX579 (although I do dilute it about 1:4 before using it).
Not saying it isn't dangerous, just that it's no worse than, say, chlorine
bleach or gasoline or a hundred other common household chemicals.
> The question is how do you avoid using more than you need?
Easy, just take a look at what the stuff costs!
> What happens to the excess?
As you say, dilution. Flush it down the drain.
-- Randall
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