Lesco has sold RUST ERASE for year. It is oxalic acid. Of course the great thing about oxalic acid is the minimal impact on soil and plants
Paver's and other surfaces where I don't want to take a chance, I use Household Vinegar. From an experience on Black Top road I found oxalic acid clean TOO good and leaves a Clean spot that takes years to blend in. Yes it takes Multiply applications of vinegar which is a PITA, but having to replace a Paver Brick Driveway isn't cheap.
Muriatic acid not only tears up surfaces, But it can sterile the Ground and kill plants and trees.
"TG doesn't give a rats ass about being "Responsible" as long as sales/production quotas are met. That's it in a nutshell. A recipe for disaster IMO." Ted Putnam 2/28/14
You can lead a Donkey to water but you can't make the Jackass Drink
"As Americans you have the right to be stupid." John Kerry
"Life is tough, but it's tougher when you're stupid.” John Wayne.