Hello there.
I bought this Chesterfield-style couch & chair. It was abit rough but i liked the patina. What i didn't like so much was how light the brown colour had turned.
So first i tried leather conditioner which just made it brighter and shinier. Tried different kind of oils which didn't do much at all. I think it has some kind of film on it. Tried some paint thinner under a cousin which at first made the brown alot lighter. If i kept rubbing for awhile it turned much darker (something i would like). This was on a dark spot tho which haven't been exposed to the sun, so it's original brown was already pretty dark.
Worst problem is i think i used abit much conditioner over some cracks which turned them black, and it wont go away. So thinking of trying to remove the film with acetone then oiling the leather to match the cracks, as i pretty much already ruined it.
Uploaded a picture of it, you can see how light the cracks was at the top right, which i didn't mind. The picture doesn't do it right as the cracks are even darker.
https://imgur.com/a/XGrdi
