Hi @Admiral Kolchak, Apologies for being late to the conversation but here are some general tips for looking after leather : Preferably before using anything with leather, said leather should be coated in in a protective wax, the more beeswax said protective wax contains the better as beeswax is among the best nautral sealants one can apply to leather as this protects said leather from sweat, water, dirt, oil, grime, etc, even dust to some degree, or at least makes dust easier to wipe off with a protective wax coat. Before or after having a protective coat applied to leather, using a damp, lint free cloth or paper towel to wipe down the leather makes sure the surface leather is clean so you don't seal in any contaminants. Dettol or Kirkland baby wipes also work well for keeping leather clean before & after being sealed by protective wax though it is important to note to not to apply too much pressure when using said wipes as even the light alcohol base in those wipes can potentially damage the leather. The same goes for any soap, liquid soap especially though as long as it has low or no alkaline, the better it will work for cleaning... Applying gentle heat (low heat from a hairdryer or heat gun 10 cm from leather surface) does help seal in protective wax & generally makes it last longer. Leather usually blackens due to being unprotected &/or untreated by said protective wax though it is important to note, applying protective wax to leather will darken it slightly as it gets soaked in but leather will usually return to or close to its original colour. It is possible to 'restore' the Stellia's original colour to some degree though it may already be too late given it wasn't protected prior but doesn't hurt to try, by using a 'natural' based leather conditioner, as long as it doesn't have any petrol based chemicals. As stated above, low or no alkaline soap also helps clean the leather, especially before using any leather conditioner though I would caution against using anything classed as leather cleaner as that generally strips away the surface leather. Hope this all makes sense & works for you, feel free to ask me more if you need. Hope you have a great day !