u/Any_Cantaloupe_129

I picked up these Charles Tyrwhitt boots recently and am cleaning them up. After I saddle soaped them I noticed what looks like a water mark on the front of the ankle. I thought maybe that is where I had scrubbed more vigorously and removed more shoe cream, so I used acetone on the darker areas with a cotton ball (I am going to dye them anyway). The acetone soaked in more on the darker area which led me to think its not extra cream still on that area. I didn't spend a lot of time rubbing it with acetone, but some more of the finish was coming up. Any thoughts on what this may be from would be appreciated. Thank you all!