In one sentence, describe what the following article is about:

Use a mop and warm water to wet your tile flooring before using cleaning agents. Tile is porous and will absorb the water to prevent chemicals from penetrating the tile. You can loosen tough dirt before wetting the floor with a broom, or after the floor is wet using a plastic pot scrubber. Fill a bucket with warm water and a couple of drops of dish soap. Scrub the floor with a nylon or natural bristle brush. You can leave the cleaning solution on the floor for ten to fifteen minutes, as long as it you don’t let it dry on the tile. After scrubbing, rinse the flooring – twice, if possible – with plain water. Dry the flooring with terry cloth towels, if needed. If soap and water haven’t worked, try a household or commercial floor cleaner intended for ceramic tile. Find an inconspicuous area and make a small test spot with the cleaner. Use acid-based or chemical cleaner with caution, only if necessary and always following the manufacturer’s instructions. Make sure to thoroughly pre-wet the floor first, and completely rinse it afterwards.  Acid-based cleaner may be necessary to remove lime or cement mortar staining. Never use abrasive cleaners like powdered cleansing agents, baking soda or even creams advertised as “mildly” abrasive. These can damage the tile’s surface and design. Fill a bucket with an ounce of Murphy Oil Soap, 1/2 cup white vinegar, and two gallons of warm water. Dip a toothbrush or other narrow brush into the bucket and gently scrub the grout. Avoid the tiling as much as possible.  Since some contact with the tile is inevitable, perform a test first in a small area. Allow the diluted cleaner to air dry on the grout.

Summary:
Pre-wet the floor. Scrub mold or mildew with soap and water. Rinse the tiles. Test the floor before using any chemical or acid cleaner. Brighten the grout.