if it's pre-owned it's hard to say, as it can be due to the tanning process or spillages. If it'spillsages or effects or earlier treatments, you could just clean it. If it's poor tanning, I've found a website below that has some information. You have to be careful cleaning leather - as some cleaners are alkaline (Leather is acidic. Its pH is measured at between 4.5 and 5.0. Household cleaners are alkaline. Windex, 409, Mr. Clean are all common household cleaners with a pH of exceeding 9.0 and topping out at 11.45 (Windex). Mine was dirty, not sticky and I tried the following (avoiding household cleaning products) I tried vinegar mixed with olive oil http://www.topcleaningsecrets.com/house/how-to-clean-a-leather-sofa-at-home.html It didn't particularly lift any deep dirt but made it feel nice. Might help? We used a leather car seat cleaner - I think we go it on the hardware shop across the road from the M&S on Lordship Lane. That made it clean! We also have a leather cleaning set from the DIY shop nearer to Goose Green. That wasn't too expensive ?10-?20 - something like that. Haven't used it yet. Got bit bored of the time it was taking.... Whatever you do, try it on an area out of sight, so if it does strip the colour, you won't have to worry too much. Mine's cream and a bit lighter in patches but it may be just because it's actually REALLY clean in places! This is also informative - in the effects of the tanning process (if it had not been tanned properly) http://likeleather.blogspot.co.uk/2011/07/leather-couch.html