Coopers have provided me with excellent service and good value for money. Ten years ago I paid £80 to have my parent's gravestone professionally cleaned. This would now cost in the region of £120. Following the professional cleaning the gravestone gradually discoloured and after three years required cleaning again. On recommendation I used Coopers Stone Cleaning solution and the results were extremely impressive. Superior to the professional cleaning job. So impressive was the result that people thought I had replaced the headstone. Not a mark remained. The long term protection provided by Coopers solution means that seven years have elapsed before another clean is necessary. It could be left longer but at about £4.50 a clean it is inexpensive to keep the headstone in pristine condition. Thank you Coopers for a quality product and your prompt service . Steve of Lincoln UK.