Is it possible to grout over grout thats already down?
Clean with hair shampoo with cloudy ammonia added use about 5% mixture to 9 litres of water hot water then after soaking tiles say about a squares metre scrub along the grout with a stiff brush but before scrubbing put out the next metre of mix so you are not waiting for the soak it works I was a cleaning company manager trouble shooter for 25 years.~~
