This has been discussed several times before, but worth mentioning again- pure neetsfoot oil is effective on pump leathers, but a great many products called 'neetsfoot oil' are diluted with all sorts of other cheaper substances, which will cause the leather to go gummy or otherwise become ineffective, so it pays to research.
@james charles bennett Yes, saddleries, but not forgetting on line suppliers. My latest can came via ebay from a firm called enquiries@lubrisolve.co.uk - no idea of their ebay name. The label on the 500ml can does say it is pure. D.
