Suede is not the most stain-resistant of materials, even when it has been treated. Combine an absorbent material with a stubborn, oily substance and you have a true cleaning challenge. High grade diesel might be clear and evaporate easily, but it leaves behind an oily residue and distinctive odour. Low grade diesel or, worse, engine oil is even more ruinous. It isn’t always impossible to remove diesel from suede, but it sometimes requires several tries. If all else fails, you might have to dye your shoes, boots or jacket to cover the stain.
Blot the diesel lightly with paper towels immediately, discarding each towel and repeat until you have removed the bulk of the stain. Do not rub or press hard while you are doing this.
Coat the remainder of the stain with a thick layer of baking soda or talc and leave for several hours. These powders draw up oily substances.
Drip white vinegar onto a clean cloth and carefully blot the stain, taking care not to dampen the suede around it.
Take the item to a dry cleaner’s if a stain remains and the item is important to you. Special suede cleaning products are available but they tend to be little more effective than vinegar. At this point, if you are going to spend money, you might as well spend it on professional help.
Dye the item with a black or dark brown suede dye as per the instructions, if all else fails and the remaining stain is ruining the item’s appearance.
The pungent chemical scent of diesel, and the lesser one of vinegar, will dissipate in time. Hang the item in a well-ventilated room or outside, if the weather is fine, and it should be gone in a few days.
Treat new suede clothes or shoes with a suede protector spray, widely available from shoe shops, which waterproofs and makes suede slightly more stain-resistant. It won’t be enough to fully withstand diesel or oil, though, so avoid wearing suede jackets or boots when you are fiddling with your car unless you actually like the stained look.