[TR] rust removers recommendations

[Dave1massey at cs.com]

In a message dated 6/13/2011 12:53:04 PM Central Daylight Time, 
TR3driver at ca.rr.com writes: 
> Phosphoric acid is not very hazardous, though, and in fact is an 
> ingredient
> in many soft drinks.  After reacting with rust, you have iron phosphate 
> and
> water.
> 

And we have hydrochloric acid in our stomachs, that doesn't mean I want 
laboratory grade acid splashing on my skin or eyes.  This is a case where the 
solution to pollution is dilution.  Most domestic water systems in this 
country have enough lime and other dissolved minerals in larger enough quantities 
to neutralize the acid. 

The acid that does react with the rust does leave behind just phosphate and 
water.  The question is how do you avoid using more than you need?  What 
happens to the excess?

Dave