As I came back home today, I have found patches of oil along the alley, over the entry door, and many of my plants, mostly succulent plants. I'm not much worried about the fruit trees, because their response is fast enough, and they can re-grow new leaves instead of the ones damaged by the oil.
After a short inquiry, I have found-out that some construction work was going on. A truck was unloading some building materials next to my entry. During the unloading process, the hydraulic system operating the lever has bursted, spilled oil and sprayed the rest over a long radius.
Is it ok to leave the spray? I would not use detergents to take it off, as this may cause more damage. The oil does not evaporate, but will the sun's radiation do the work and break-up the material? What is the safest way to remove it without damaging the plants?