making light oiled reins darker

Dose anyone know what to use to make light oiled reins darker. I got these billy royal reins at a good deal. But there light oil all my tack is med to dark oil. Saddle a circle y color called walnut. Dose anyone know how to darken the leather so it will be close to my tack color.

Oil them with neatsfoot oil! :) You'll want to do a less than noticeable spot first, just to make sure that the color is right, but it should do the trick.

I'd also advise making sure the oil is 100% neatsfoot because neatsfoot oil sometimes has other oils added in that can cause any natural fibers to degrade, and even though your reins probably don't have natural fibers, you might eventually want to oil something else with natural fibers...

Use neatsfoot oil - Fiebings Prime Neatsfoot Oil Compound- Western Horse Saddles - Saddle Online