Try to get major mud off the surface before cleaning with Saddle Soap. Saddle Soap / Sponge, polish polish Brush soft Bristle Brush, sole Edge Heel Dressing.
Exotic Leather (Made from critters you mostly do not want to meet while they are alive). Dip a q-tip in olive oil and rub in a circular motion over the scratch until it is less visible. Try baby wipes instead of soapy water if you like.