True - any chemicals use must not only be flushed, but neutralized with baking soda, etc. (reverse pH factor). Test water must come back 7.0.
The acid-dipped S/S and steel funny cars all disintegrated into piles of dust, except the one (Landy?) who neutralized his.
It's almost cost-effective in supplies (the acid actually used is much, but you need a lot for the fill), but it's labor intensive and scary to do, and dangerous.