SL/R129: 500SL Soft Top Stain
The hydraulic fluid is mineral oil based. That said, strong solvents are effective for the stain, but may not be good for the canvas. Try a 4:1 mix of water to woolite and a soft brush. Apply with spray bottle, bruch, rinse thoroughly; repeat as needed. When you get the oil diffused, you should apply a water repellant; Raggtop brand is a good one.
Bob



