Scrub with diluted ammonia to remove discolorations in concrete, soft drink mix to remove rust stains, and oven cleaner or WD-40 to remove oil and grease stains. Scrub the affected areas and then rinse them well with a hose. Reapply cleaning solutions as many times as necessary.
Oil and grease stains are difficult to remove, but oven cleaner or WD-40 may work on small blemishes. More heavy-duty stains need an absorbent solution to draw them out before scrubbing. Mix baby powder, cat litter or trisodium phosphate with water to make a paste, enough to completely cover the affected area in a thin layer. Allow the paste to dry before sweeping it away, scrub the area with a nylon brush and rinse it with clean water. The absorbent solution may need two or three applications to work completely, and some oil stains may leave a permanent mark.
Other common stains include paint, epoxy and mildew. To remove household or spray paint, apply a paste of paint thinner and water to the area and let it sit for 10 to 20 minutes before scraping it away. For spilled epoxy, carefully burn the stain away with a blowtorch. To remove mold and mildew stains, use household bleach mixed with laundry detergent and water, scrub and rinse the area clean.