Cleaning hydraulic fluid off concrete can be a difficult task without the right methods and materials. Before beginning, safety should always come first - make sure to wear proper protective gear such as gloves and goggles when handling any sort of hazardous material like hydraulic fluid. First, use absorbent pads or rags to soak up as much of the spilled fluid as possible; for larger spills, using an industrial vacuum cleaner may help with removal. If there are still some traces left on the concrete afterwards, try scrubbing it with a degreaser or detergent specifically designed for cleaning oil and grease from surfaces such as driveways or garage floors. After letting it sit according to product instructions, rinse thoroughly with water before drying completely with an absorbent cloth. Additionally, you can use cat litter over large areas- simply spread generously over all affected spots and leave overnight before sweeping away in the morning. As a last resort if these methods don’t work out, try renting a pressure washer from your local hardware store and follow directions carefully so that you don't damage your concrete surface in the process!