Is it possible to remove rust stains around tie holes?
Yes, a solution is made of one part by weight of sodium citrate to six parts by weight of water. This solution is brushed onto the rust stain at short intervals so that the concrete absorbs the solution. Crystals of sodium hydro-sulfite are then ground to a powder and applied to the moist wall. A paste of fuller's earth and water is then applied to the surface, covering the crystals. The paste is allowed to dry for about 10 minutes and then scraped off. This procedure is repeated until the stain has been completely removed.