If your ullu accessory gets wet, pat off the excess water with a soft towel or a tissue paper. Don’t wipe hard - you will just drive water deeper inside the leather.
For light grease or oil stains, use a damp tissue or a baby wipe. For bigger oil stains, apply a little baking soda or corn starch on the grease, and wipe off with a microfiber cloth after a few minutes.
Use an eraser to remove the dirt and grime layer that settles on the case over time. Simply rub the eraser in small, soft strokes, and wipe off with a soft microfiber cloth.
You may also use an eraser to lighten any scratches on the surface.