How to Clean up Oil Spills in a Garage
To clean up oil spills in your garage, all you need is coconut coir, soap, and hot water. Start by pouring coconut coir on and around the oil to soak it up. This is much safer than using kitty litter or clay. Use a brush to move around the coconut coir and soak up all the oil. Once the coconut coir has soaked up the oil, throw it in the trash. If there's any residue left by the oil, squirt some dish soap on the stain. Then, pour a tiny bit of hot water on it to help it spread out. Scrub the stain with a stiff brush to work the soap into the floor. Wait 10-60 minutes, depending on the size of the spill, before you soak up the soapy water with paper towels.
Absorb the surface oil with granular coconut coir (coconut husk - a far safer alternative to the usual application; kitty litter/clay). Pour around the oil spill to stop it from spreading further, and on top of the oil. Use a brush to move around the coconut coir and soak up all the oil. Check the label for health and safety information before using any oil absorbent. Some of these materials may be dangerous to inhale. Dispose of the coconut coir. If you handle a lot of waste oil, buy an oily waste can. These are ventilated to cause the soaked litter or rags to dry more quickly. Do not try to wash away the litter. Motor oil can harm plants and pollute storm drains. If not all the oil is absorbed, hosing it may just spread the stain. Squirt dish soap over the stain. In most cases, the litter will still leave a light oil stain on the concrete. Squirt ordinary liquid dish soap onto this stain. If the stain is quite dark or large, you may want to try the methods listed under Old Oil Stains instead. An engine degreaser may work as well. Add hot water. Pour on a tiny bit of hot water and mix it into the soap, just enough to make it spreadable. Brush the mixture over the oil stain until the soap covers it in a thin layer. Scrub thoroughly. It can take some effort to drive the soap into the oil stain, especially if it's penetrated deeply. Scrub with a stiff brush until there are plenty of suds. Do not use a wire brush, which may scratch the concrete. Absorb after 10–60 minutes. Wait at least 10 minutes for the soap to pull up the oil, and up to an hour for heavy spills. Once ready, absorb the dirty soap mixture using more kitty litter, paper towels, or a disposable sponge. Dispose of all oil-soaked materials as you handled the first round of kitty litter. Blot the paper towel or sponge directly onto the soap, lifting up. Do not rub it against the floor. If the soap is difficult to pick up, dilute it with warm or hot water. Absorb all of the water before it carries pollutants to a garden or storm drain. Repeat as needed. Oil spills often take two or three scrubs to remove entirely. If the stain is still dark or the scrubbing didn't have an effect, try a specialized product, as described below. You do not need to repeat the initial kitty litter soak, just the soap treatment. Scrub with an alkaline degreaser. This product, also sold as "concrete cleaner," is essentially a powerful soap available from concrete distribution outlets. It tends not to work well on non-porous concrete, or on heavily stained areas. Here's how to apply it: Dilute with water according to label (Skip this for heavy stains.) Apply over the stain. Scrub hard for several minutes. Leave it for several hours. Blot the residue with rags, or lift it with an industrial wet vac. Treat with an enzymatic or microbial cleaner. One of the newest ways to deal with oil is to break it down with an enzyme or microbe. These can be very effective if you can find one formulated for your specific oil product. Look in hardware and home improvement stores, or online janitorial supply stores. To clean up the stain, just pour the cleaner onto the oil and let sit for several days or weeks. You can try a general-purpose enzymatic degreaser, but for best results find a product that mentions your specific oil (such as motor oil) on the label. Check the label for instructions. Some products require water or scrubbing, but most do the work on their own. There may or may not be residue left over once the product has done its work. If there is residue, check the label for disposal instructions. This residue is typically harmless, and can be washed away to the soil or storm drain. Try this for stubborn stains. A homemade poultice is a powerful and often a cost-effective option. It should deal with most old, stubborn stains, but can be tedious to mix and apply over a large area. Take safety precautions. Poultices contain hazardous solvents, which may be flammable, dangerous to inhale, or corrosive. Check the solvent label for safety instructions before opening. At minimum, work in a well-ventilated area and wear rubber gloves. Keep children and pets out of the garage. Some chemicals may be banned in your area, especially sodium orthophosphate (aka trisodium phosphate). Check regional laws or ask an environmental agency before ordering a solvent from another state or country. Choose a solvent. Every poultice contains a solvent to break down the oil. Here are a few possibilities, roughly in order from common & mild to specialized & powerful: Acetone Lacquer thinner Mineral spirits 1 pound 6 oz (0.6kg) sodium orthophosphate in 1 gallon (3.8L) water (Very corrosive to skin. Use only as a last resort.) Note — Start with a small test batch. Mix with absorbent material to form a paste. To turn the solvent into a poultice, mix it with an absorbent powder until you get a thick paste, similar in texture to peanut butter. Here are common options: Baking powder, flour, or powdered sugar (less effective but easily available) Kitty litter, diatomaceous earth, kaolin, or talc (usually more effective) Whiting chalk or fuller's earth (for non-acidic solvents only. Whiting chalk is recommended for sodium orthophosphate.) Test a corner of your garage. The solvent may damage your concrete finish. Brush a little of the poultice onto a hidden area of the floor. Wait for it to dry. If it damaged the floor, mix a new poultice using a different solvent. Apply the poultice. Spread the paste over the oil stain. Ideally, cover the whole stain in a layer at least ¼ inch (0.6 mm) thick. Spread it slightly beyond the edge of the stain to make sure all oil is covered. Leave on for 24–48 hours. Most poultices take about this long to dry. If the poultice dries before then (common for mineral spirits poultices), scrape it off and apply a new poultice. Continue once at least 24 hours have passed. Scrub with plain water. Brush away the dried poultice. Scrub the stained area with water. Dispose of the poultice according to local hazardous waste laws. Repeat if necessary. Stubborn stains may require a second or third application. If there is very little change in the appearance of a stain, try a different solvent or a commercial product instead. 
Absorb the surface oil with granular coconut coir (coconut husk - a far safer alternative to the usual application; kitty litter/clay). Dispose of the coconut coir. Squirt dish soap over the stain. Add hot water. Scrub thoroughly. Absorb after 10–60 minutes. Repeat as needed. Scrub with an alkaline degreaser. Treat with an enzymatic or microbial cleaner. Try this for stubborn stains. Take safety precautions. Choose a solvent. Mix with absorbent material to form a paste. Test a corner of your garage. Apply the poultice. Leave on for 24–48 hours. Scrub with plain water. Repeat if necessary. 