Cleaning and Protecting Garage Floors
Concrete garage floors are very strong and last long but they are also porous and can be stained by the oil, antifreeze, grease and gasoline that may spill and splash onto the floor. It is possible to clean them to look almost like new and they can be left like that or painted with concrete paint. It is best to clean a spot as soon as possible. The longer it is left on the floor the harder it will be to remove.
After the garage has been cleared out the floor should be vacuumed to remove loose sand and dust. The oil stains will be the most obvious. They can be cleaned with an alkaline detergent. Mix a little with water to make a thin paste and put it on the oil spots to soak for a few hours. Then use a pressure washer with hot water and even strokes to slowly rinse off the detergent. Alkaline detergent is toxic so only use what you need.
There are more eco-friendly ways to remove oil stains from concrete. Scrub the stain with liquid dish soap and a little water. Some put cola on the stains overnight before washing. Baking soda, cornmeal, sawdust or kitty litter will absorb the oil. Be sure to wet it before you sprinkle the powder, then brush with a stiff brush. Automatic dishwasher detergent and hot water also work well. After each one of these remedies, rinse with plain water. There are toxic chemicals including muriatic acid and trisodium phosphate that work well, but you need gloves, goggles and protective clothing and these chemicals should not be washed down storm drains. If harsh chemicals are used, baking soda should be sprinkled over the entire area to neutralize any traces of the solution.
The best way to keep a concrete garage floor looking and smelling fresh is to clean it as soon as it is needed. There is garage floor epoxy or paint that can be applied after cleaning and sanding that will not stain as easily as concrete. There are also garage floor mats specifically designed for putting under cars to keep the floor clean.