I am presuming OP means some kind ot Neatsfoot oil or compond. I would find another product, some kind of non-oil conditioner to apply to the reverse of fenders. You might need to apply conditioner several times to soften.
Oil is heavy. It will come right thru fender to the rough out, as well as getting greasy on other stuff. Once applied, any oil is hard to get off, especially if leather gets saturatedâŠ
Go with a conditioner first, aplying in several coats, with drying time between applications. See what fenders feel like then. It does take using time to get fenders real soft and flexible. You can always go back with oil if you are not happy. But you canât get oil removed once it is applied, it has to wear off. Personally, I hate how oily leather feels on my hands. Just like any other petroleum product, not meant for skin, which is what leather is. Olive oil has a totally different feel, result on leather, even though both are âoilâ products.