I saw on the Internet there is a product called Rid O Rust. I purchased
a couple of gallons of it from a local distributor. It worked
"alright", but seemingly not as well as I had hoped. I found myself
pouring it into a quart sized squirt bottle and running around getting
only small patches after using an entire gallon.

Does anyone have a good technique involving perhaps a common acid from a
Pool Supply store, Lowes, such as TSP, Iron Out, Ecotec, or Muratic Acid?

Thanks!
Mike