How to Sand Concrete » The DIY Hammer
The best way to clean a concrete surface is with a mixture of 1 cup of trisodium phosphate or 2 tablespoons of degreasing dish fluid with 4 gallons of water. Mix well and scrub the entire surface down with a stiff brush. Once clean, rinse the surface down, then mop up and leave to dry or use a wet vacuum to remove the remaining water.