Removing adhesive residue from leather?  

Use
lighter fluid to remove the goo, but you'll have to recontion the leather after. In my experience, lighter fluid is not too caustic, although it may dry the leather a bit.
Good luck with it.

Hair dryer
Use a hair dryer
The heat will make the rubber in the clue (assuming it is from a sticker) plyable and removable.
on a soft cloth (Depending on the colour of the leather) you can use a small amount of teak oil or linseed oil to dissolve the clue.
Wipe the oil of the leather and what you are left with is a shinier area.
Rub the entire leather surface with leather cream and allow to dry before you buff with a soft cloth.
Good luck
Simon

I would try lighter fluid long before
I would use a hair dryer, to be sure.

the pros know
if you intend to try both lighter fluid and a hair dryer, be prepared to run like mad and grab your photo albums on your way out of the burning house.
i'd be inclined to first contact a business that deals exclusively in leather [like wilsons] or a more local-level person who works in the craft. they've undoubtedly encountered more situations for the care and cleaning of leather than we might imagine.
when in doubt, contact the professionals. if they scratch their bewildered heads, then you can always resort to highly flammable chemicals. just remember to stop, drop and roll.
the good news is that eyelashes will usually grow back over time.

thanks
Thanks for the suggestions. kdc, I believe that barry was recommending trying lighter fluid instead of the hair dryer approach, rather than in combination.
As far as the identity of the residue, I don't believe it is from a sticker since the area is rather large. I suspect that something was spilled on it, but of course I can't be sure.

We need smilies on this...
We need smilies on this forum. 🙂

It made me smile
just the thought of using hair dryer and lighter fluid in the same operation and the resulting inferno.
Maybe I need to stop watching Mythbusters and their explosive research.
I have used hairdryer on stickers for years as that result is the best. Call me expert or not but it is A solution not THE solution.
Many are out there.
If you have leather with a large patch on it of unknown residue the best option is to, if possible, replace the leather or live with it.
If it is an asthetics question then live with it. If it is a matter or repairing damaged leather, which is absorbant to most liquids, then hey throw your wallet at it maybe the wife too, just for good measure!
I need the weekend to begin VERY soon or the coffee to be weaker!!
Simon

simon
weak coffee is only for the weak; keep it nice and thick and i'll be over for a warm slice.
i suppose the method of removing the goo will depend in part on the type of leather in question. different finishes [or ways in which the leather was tanned] may well suggest a variety of approaches for the most desirable results.
of course, doing a test in an inconspicuous location is always a prudent first step. otherwise the anticipated solution could end up making things much worse than the original problem.

KDC:
Of course, I would not suggest using both lighter fluid and a hair dryer! I'd say, lose the dryer altogether.
People are weird about lighter fluid, not realizing that many other cleaning agents are as flammable as lighter fluid.
Based on my experiences, lighter fluid removed glue and some staning, without ruining your hands or the finish under the glue.
I've used it for years, tried Goo-Gone when it came out, and went right back to lighter fluid...it's substantially superior to Goo-Gone.
I would never use a hair dryer on leather.
If you're so nervous about lighter fluid, you might take an older washcloth that you don't care about and put it in a bowl of water and put the bowl into the microwave, to get the washcloth real hot, then lay the wrung-out washcloth on the glue and see if that looosens the glue.

jus' kiddin'
i was just joking about using lighter fluid and a hair dryer together. in a strange way i thought the notion was ridiculously funny, similar to smoking a cig when filling your car with gasoline.
maybe my dry sense of humor could stand to be moistened just a bit. sometimes it's a challenge for me to communicate subtleties in the written format.
anyway, to echo your experience, barry, i know lighter fluid can be very effective for many uses beyond its advertised purpose. just a few drops of it in a shot of tequila seems to help take the annoying edge off of a fussy kid.