The white grout on my ceramic tile floor (approx. 500 square feet) was so badly discolored that nothing I tried (including vinegar, oxybleach, etc.) would restore the color. I used your products, the Easy Clean and Colorant/Sealer on my floor. It was quite a bit of work (the knee pads are a life saver) but the results are amazing. You really don't need any skill to use these products -- just follow the directions. I love my new floor! I would also like to note that your customer service is the best -- The rep answered all of my questions and gave me some helpful pointers.