"I am a perfectionist and have tried everything including having my window washer clean the glass for our shower stall but we were unsuccessful in getting thje hard water marks out. I was seriously considering replacement glass—then heard about Mark and Diamond Seal and decided to try it and I am delighted with the work and how my glass looks after Mark cleaned and sealed the glass. I use the cleaner weekly to keep it looking great and I am very pleased."  

Pat, Portland, Oregon