In general leather should not be exposed to water (or other liquids) or direct heat.
For our full-grain calf leather we recommend that any liquid spilt is wiped off gently with a lightly moistened cloth and left to dry naturally away from direct heat or sunlight. Full-grain calf leather is more susceptible to staining than other leathers, because it is the surface layer of the animal skin, the grain has not been sanded, buffed or polished or had any additional surface film applied to it.
Over time full-grain leather takes on a natural patina or film from everyday use. This natural patina is a combination of the oils from your skin and other surfaces the leather comes into contact with. This gives full-grain leather its own wonderful character not dissimilar to the patina that develops on old wooden furniture and brass objects. Over time this patina forms an increasingly protective coating to the leather adding to its durability and individuality of character. At this stage care should still be taken but staining is much less likely.
The zander and salmon leather in your Creel accessory have been treated with a thin protective coat, similar to that used on other exotic leathers; this is to protect the scale pockets and stop them from lifting when in contact with other surfaces. Cleaning should be done with a very lightly moistenened cloth without any vigorous rubbing or scrubbing.