Originally Posted by
Neil Miller
The main reason you would choose 100% neatsfoot oil over the compound formula is that you don't know what is in the compounded oil - that's all. It is likely to be a mineral or petroleum oil, so it shouldn't matter to horn scales anyway. It matters most to leather strops, but these aren't the question in this case. Most oils that you could put on your skin would serve - horn is only like the material our nails are constructed with. If you wouldn't use it on your hands, don't put it on the scales.
What's worrying is that such a short immersion in water should provoke such a degree of oxidation, if indeed that's what it is. For black scales to turn white you usually get a drying of salts on the surface that is white and powdery, or a mould that looks pretty much like the same thing, or you have got delamination just under the surface to a large degree. Horn is made from thin layers of material, and if separation (ie delamination) occurs, then the change in how the light penetrates the scales becomes apparent and you get a lightening effect. The trick is to fill that delaminated area with something of a similar refractive index, such as oil. Thinning the oils with spirits or turps (test first - not all oils thin in the same stuff) will help the delaminated areas wick it up, then you remove to a thicker (full strength) oil for a rather long time - I have left them fop anything from a few days to a few weeks. Sometimes the effect is so profound that they look magically restored, and the oil is not going to oxidise away very quickly after prolonged soaking, especially if you buff the scales and finish with a layer of wax well-rubbed in. Any buffing agent you use does not want to have any water or ammonia in it - some of those metal buffing polished have a distinct whiff of ammonia. Originally they would have used tripoli powder mixed with wax or oil. Lapping compound (fine) would do it. A light sanding followed by buffing will have them looking very shiney - do the sanding before oiling, though.
Regards,
Neil