Bring to the boil half a pint (250 ml) of linseed oil, let cool & when nearly cold add half a pint (250 ml) of vinegar. Mix together well & bottle. By application rub well into the leather & buff up with a soft cloth.
Now I've no idea if it works or not (no personal experience with this particular tip) but it's a tip out of a book called "Household hints" by Hilary Davies, we've tried other things that are suggested & been quite pleased with the results.
To be on the safe side try it somewhere not so obvious initially to see what happens & good luck with it.
