1. You can use toothpaste, a toothbrush and elbow grease.
2. Use a scraper or putty knife to remove stubborn debris. Use a nylon scrubbing pad dampened with dishwashing liquid to remove stains from grout. Apply grout sealer twice a year to prevent stains.
3. You can apply Lemon Oil to your kitchen tiles to keep them cleaner longer, apply sparingly to the tiles then wipe with a soft cloth to remove some of the oiliness
4. Baking soda and a wet old tooth brush or nail brush seems to work excellent for me
5. Toothbrush and kitchen gel cleaner with bleach.