How do I clean dirty tile on the kitchen floor?

Here is a great tutorial for cleaning your grout: https://www.bobvila.com/articles/cleaning-grout/

I clean mine with vinegar water. Put a ratio of 1:10 in a bucket (1 being the vinegar). Use a deck brush to lightly scrub the floor, then give it a warm water rinse. It might take a little time to get the grout clean if it is dirty, but the acidity will bring the grout back to it's original state over time.

Grout can be problematic, Heres some other recommended cleaners

The Best Way to Clean Grout-EVER!!! | Hometalk

https://www.hometalk.com/diy/clean/bathroom/the-best-way-to-clean-grout-ever-2295735?expand_all_questions=1

https://www.hometalk.com/diy/clean/floors/homemade-grout-cleaner-recipe-41693881?expand_all_questions=1

https://www.bobvila.com/articles/cleaning-grout/#.Wi6YzKZOmf0

https://www.hometalk.com/search/posts?filter=clean%20grout

Additionally

Painted Tile Grout Refresh with grout pen

https://www.blesserhouse.com/painted-tile-grout-refresh/

1 cup baking soda

1 cup white cleaning vinegar

1 Tbsp blue Dawn

2 gallons hot water (I boil about 1/3 of mine)

Lysol Lime & Rust Remover Toilet Bowl cleaner and magic eraser for particularly stubborn stains, especially grout.

Once grout is clean, re-seal.