Mink oil comes from the skin of a mink.   Neatsfoot come from the hoof of a cow and other animals. Olive oil from, well olives. Animal or vegetable oils are never good for leather because of the potential of rancidity.  The oil can turn rancid.

To understand why, here's a short chemistry lesson.   There are two ends of the animal or vegetable oil spectrum: There is Saturated oils on one end and Unsaturated oils on the other.   Saturated oils are really stable, whereas unsaturated oils can be unstable.

There is a scientific method for testing this.  It’s called the Iodine Value (sometimes referred to as Iodine Index).  The higher the iodine value of an oil, the less stable it is, which means more sensitive to oxidation.   Simply put, the more likely to go rancid.  

The Iodine Value of mink oil is between 80 and 95.  Neatsfoot oil runs between 69 - 75. Olive oil is way up there as well at around 85. These are pretty far up that scale. Mitt-Spit glove oil is about 1. The same low rancidity potential exists for Mitt-Spit Break-in. That means virtually no chance of rancidity with Mitt-Spit products.

Mink, olive and neatsfoot oils all have fairly high Iodine Values.  There are 3 other factors necessary.  Exposure to air (oxygen), heat and light. This is why olive oil bottles are generally green (not clear glass), are stored with the cap on tight and supposed to be stored in a dark cool place.

Your baseball glove however is outside in the sun, exposed to air and gets plenty warm.  So your mitt is exposed to all three factors: Air, Heat and Light.  If it's loaded with olive, mink or neatsfoot oil, It doesn't take long for the oil in the glove to go rancid. What does this mean to you?  Anything going rancid in the leather will help deteriorate that leather.  It will make your glove smell and is generally unhealthy. Yuk!

Mitt-Spit products on the other hand is made from an oil that is often found in cosmetics, or even as a food additive.  It's very safe for your mitt too.  As mentioned, Mitt-Spit glove oil and Mitt-Spit Break-in have an iodine value of about 1.  For the sake of your glove,use Mitt-Spit products. If you invest in the correct care products, you’ll never be sorry. Go here to buy Mitt-Spit Products.