Try this from do it yourself.com. Other than that I don't know what the stuff is.
Rust Stains: Make a paste of 1 part sodium citrate crystals to 6 parts water and enough whiting or fuller's earth to make a paste. Spread paste on rust stains and allow to dry. Scrape off. Rust should be removed. Repeat if necessary.
I think Jim took care of the other question. Either epoxy in the holes to firm them up or drill new holes for bolted railings. They make bigger and better concrete anchors now so maybe getting some of them and redrilling wider or deeper may help if that is an option with your style of railings. Find a store that carries a full line of fasteners.