Hi Sparks, I had heard so many different things so went my local equestrian shop and they told me about this 'Flexalan' lanolised leather dressing, you clean off the muck with a damp cloth first, allow to dry then use a paint brush to apply a thin coat, allow to dry and repeat. Seems a bit off faffing but my jacket is like new again and it has increased it's waterproofiness lol. The 500ml tin cost £9.99 and I reckon it will last years. Good luck with whatever you go with