My grandfather used to make his own black boot polish .. he started out with Dubbin and mixed in something that he called Niger Black ... he used to buy it from the local chemist ...
I suspect that it was what is now called Nigrosine or Solvent Black - it's an aniline based dye ... it was sold in the UK
J.E. Moser's 845135, Finishes, Wood Stains & Dyes, Water Soluble Nigrosine Black Aniline Dye, Package Of 8 Oz: Amazon.co.uk: DIY & Tools
But it looks like it's not currently available ... probably the H&S wallers have got their hands on it and it's been banned. More than likely that if you eat enough of it then you will get cancer ....
I worked in the dry cleaning industry for a while and we used to clean and refurbish suede and leather garments .. after coloured suedes were cleaned they lost their colour and returned to their natural skin colour. We used to respray them using liquid leather dyes which we bought in industrial quantities.
Occasionally, we got it wrong and I remember answering the phone to one irate lady who had put in a pink suede jacket and got a green coloured one back ... she knew it was hers from varying distinguishing marks and was not impressed that it was now green. I told her that the cleaning process occasionally caused the dye pigments in garments to change colour and if she returned it to us then we would see if we could resolve the problem ... it went through the cleaning again and we redyed it pink and the lady was happy ... I know - I'll never get to heaven with the lies I've had to tell at times ....
