How do you keep them clean? I read that dirt gets in the cracks. Do you have a similar product without the groove?

The best way to clean our Evolution Rubber Tiles is to sweep any large dirt and debris with a broom. For any stuck-on dirt and grime, we recommend using a mild soap and water solution with a synthetic mophead. You will then let these tiles air dry. We don't have any smooth topped Evolution Rubber Tiles, but we do have a Diamond topped version that doesn't have the smaller grooves.