How can we remove ink stains from the floor of an office supply area? The stains vary from small spatters to big spills 10 inches in diameter.
Sodium hypochlorite solution with 12 percent available chlorine is likely to be the best treatment if the ink is blue or black. You can flood it on, apply it with cloths saturated with the solution or trowel on a paste made of the solution combined with whiting, fly ash, bentonite or powdered talc. If a residual blue or black stain remains it should be treated with ammonia water. Sometimes the removal of blue or black ink stains leaves a brown stain. This can generally be removed by treating with a solution of 1 pound oxalic acid or citric acid per gallon of water, followed by sprinkling with crystals of sodium hydrosulfite (also known as sodium acid sulfite), and covering with a paste made of whiting and water. After three hours the paste and crystals should be removed, and the surface should be thoroughly scrubbed and rinsed. If any of the stains on your floor are from bright-colored inks they should be treated with a paste of whiting and a strong solution of sodium perborate in hot water. An alternative is a paste of whiting, potassium hypochlorite, potassium chloride and hot water, troweled on. The paste should be allowed to dry before it is removed.