Thanks for that suggestion, I had tried the pencil eraser method and what was on the surface came off but it looks like a bit sank in. I know from the past that that spot will more than likely be sealed to the point that it will not take dye there. I'll have to order a typewriter eraser to have on hand as needed.
This is kind of out there but maybe if you hold a piece of ice on the rubber cement for a little while it MAY turn brittle enough to break lose without damaging the surface of the leather if it comes off in one piece it may still take stain there. It's a longshot to be sure...
Except some brain cells. Be careful with MEK. I will tell you a quick little story.
I worked for a small construction company and we were doing a remodel on a restaurant. We could only close them down for three days maximum. So when we got to the removing of the vinyl based tiles that absolutely refused to come up. Someone accidently spilled some MEK on site, and we found out that it would dissolve the glue they used to lay these with years before. So here we are doing the duck walk with scrapers and pouring out MEK to get the glue up. I found out years later that I was probably at the time taking up asbestos based vinyl, and that MEK was working on my brain cells. No respirator, asbestos, and it kills brain cells. The trifecta of stupid!! The good thing so far it has had no lasting effect!!
Hey let me tell you a quick little story...………………..
OK, I've made this mistake 2,000? More times? Options: Eraser or a clean finger to remove the film of the glue, Deglaze (yes they make leather deglazing) the entire piece. Alcohol will do the same job in a pinch. Soak it in alcohol and it will dry in a minute or two. If the spot still remains, even as a darker shades spot....dye the bastard black. About two heavy coats and you'll never see it. Last but not least....add tooling to cover it. This is my last resort but it works to add a little fill in or texture to cover. Sometimes this dresses a piece up a little more anyway.
MEK will break down the fiber in your leather. It will also dry it out SIGNIFICANTLY....use it as a last resort. You'll need to really oil it down if you use it. It will also essentially turn your leather white if you use too much.