Acids can make excellent all-purpose cleaners, but not all acids are ideal for tiles and not all tiles should have contact with acids. Since acids break down minerals, they can remove difficult deposits from tile surfaces, and as long as you exercise the proper precautions they may help you to restore shine to your tile floors and walls.
Acetic acid is the prime active ingredient in vinegar. Add a cup of vinegar to a quart of water for a homemade tile and grout cleaner. Apply the vinegar to your floor with a dust mop (dampening, rather than soaking the mop) and wait about 15 minutes before rinsing, giving ample time for the acetic acid to penetrate the dirt and minerals. Although the smell might seem overwhelming at first, it will dissipate entirely within one to two hours.
Hardware stores, janitorial supply stores, and home improvement stores sell sulphamic acid cleaning products, most commonly packaged in crystal form. The crystals dissolve in water, creating an effective cleaning solution ideal for unglazed tiles. Always use cool water to activate the crystals, and avoid using on glazed tiles, since etching may occur. Apply sulphamic acid using a dampened dust mop, and allow 15 minutes as you would with acetic acid.
Phosphoric acid is a weak acid safe for most surfaces. While acetic acid most commonly occurs in natural vinegar and sulphamic acid exists in a crystallised form, phosphoric acid comes in liquid form, contained within specialised cleaning solutions like Miracle Sealants Fast Acting Phosphoric Acid Cleaner, Aqua Mix Phosphoric Acid Cleaner, and Glaze N' Seal Phosphoric Acid Cleaner. Phosphoric acid is free of fumes and is safe for unglazed tile surfaces.
Use acids on unglazed ceramic tiles, quarry tiles, vinyl tiles, porcelain tiles, and synthetic tiles. Never use acid cleaners for natural stone surfaces, namely granite and marble. Additionally, avoid using acid cleaners for glazed tiles. For these types of tile surfaces, stick with acid-free, pH-neutral cleaners like Regency Neutral pH Floor Cleaner, Stearns pH Neutral Cleaner, and Earth Choice pH Neutral Cleaner.