I recently moved into a property where the old tenent clearly never swept much less mopped the kitchen floor. The floor is only 3 years old but I can't get the ground-in dirt out. I've used ammonia and water, ammonia and Armstrong floor cleaner w/water, mops, scrub brushes etc, but there is still dirt in the many of the little grooves particularly at the edges. I'm wondering if he may have sealed in the dirt. Any suggestions!!!!!