We just had a company named Dirty Grout Be Gone come and clean all of our tile, then they colored the grout back to it's beautiful original taupe color then they clear sealed it. They did a fabulous job. It took two workers a day and a half. The tile and grout look so wonderful that it looks like it did when we bought it 5 years ago. They have a website if you'd like to see examples
Dirty Grout Be Gone-The Villages, Florida. Their phone number is 352-259-0091.