i must admit my biggest fan is an old couple, they think wfp is brilliant, they have said to me that they think their glass stays cleaner, with out me giving them the sales pitch. also i cleaned a new customer last week, old couple, and i thought to myself when i went to see them, i m going to have trouble convincing them, but when i had finished she came out and had a look and was chuffed to bits that it had removed some marks on her kitchen window and sill that had been there for ages and she couldnt remove, so another happy convert hopefully.