If you get a butter or an oil spot on your leather jacket at dinner, take it off as soon as you get home! The sooner you begin the cleaning process, the better the results will be. Lay your garment out on a clean surface. Place a small pile of cornstarch on the spot. Do not press it in, and do not touch it or move it for a day. It will draw a large part of the oil to the surface. Then, lightly brush the cornstarch off without getting it on the rest of the jacket with a dry terry cloth or toothbrush.
Then wipe the rest of the white powder away with a barely-damp lint-free cloth. Do not scrub. You can use clean water to dampen the cloth if you do not have Aquila Leather Cleaner. Let that dry and repeat if necessary. This is a good time to go ahead and clean the whole coat. Let dry completely, then moisturize and protect.
Sprayed Dye Finish
Sprayed finish hides have not been dyed in vats during the tanning process, which allows for color penetration all the way through the skins. An example of sprayed cowhide jackets are your brightly colored sports leather jackets. It is almost impossible to get them recolored once the color starts coming off. Your less expensive coats may also have a sprayed finish. You can spot a sprayed finish by checking the garment at the stitching needle holes, or at corner edges (collar tips, for example, where the leather has been pulled to turn). If the “paint” has been added after the tanning process there will be places where the finish cracks and you will see light colored flesh showing through.
Sprayed finishes are usually less desirable as they indicate extremely mass produced imports of questionable value, whereas a vat dyed jacket will allow new dye to penetrate and the jacket can be made to look new again in the right hands.
(An exception to the rule - some USA made WWII jacket replicas on the market that are made of expertly tanned and sprayed leather.)