Finally the Recipe for Floor Cleaner That Leaves No Trace

A helpful hint: use a varnish specifically designed for tile joints to shield them from moisture and stains. This will keep those tile joints that are quite exposed from becoming too filthy too fast, such in a bathroom or kitchen.

Put four teaspoons of baking soda and ten centimeters of white vinegar into a spray bottle. You shouldn’t be alarmed if the mixture begins to bubble like a little volcano; this is an inevitable byproduct of the chemical process.
Apply the baking soda-white vinegar spray to the grimy tile joints and wait for it to sit for at least one day.
After a good scrub with a toothbrush or sponge, a quick rinse with water will leave your joints looking like new!