Despite your possible preconceptions, oil-based paint can be removed from a leather item. A few common household items are all you need.
How to Remove Oil-Based Paint From Leather
Things You'll Need
Dab a small amount of olive oil onto the stained portions of the leather. Then dab the oil onto the spots. Do not rub or scrub. Just dab.
Let the oil sit on the paint spots for about two minutes. Do not leave the oil on the spots any longer than this.
Use a damp paper towel to remove the olive oil and the paint. You can dab and gently scrub in a circular motion to get the olive oil off of the leather. The paint will come with it.
Clean the leather using the leather cleaner. Depending on the type of leather, you may have a moisture spot if you do not follow up this technique with a good cleaning. Clean the entire leather item using leather cream or other cleaner so that the entire piece of leather looks clean and new.
Test this strategy on an unnoticeable part of the leather first to make sure it will not leave a stain.