I use this stuff to remove rust...just cleaned out a heavily rusted gas tank.

I pour two gallons of this in the tank and let it sit for at least 24 hours.

Heavily rusted tanks will need a second application.

I buy this at Wal-Mart in the grocery section.

I don't know if the regular Wal-Marts have it but the superstore with the large grocery section does.

It costs only $2.98 a gallon and it works better than the expensive $20.00 + a gallon rust removers.

It's biodegradable & environmentally green...just pour it down the drain.

You'll find it in the grocery aisle with the normal food grade vinegar.

This stuff is STRONGER than the food grade vinegar so don't use it on your salad!! !

I don't know how strong this stuff is (never used it), but vinegar is technically an acid.  The food grade stuff is safe but stronger grades of vinegar can actually burn you.  Just a word of caution...