[cypher]

You need to try & work out what might be causing this, treating it topically isn't likely to resolve the problem, putting coconut oil on isn't going to do any harm but don't use vaseline & I wouldn't clean the ears with peroxide either.
It could be mites, these aren't like flees so you won't find black bits on a cloth, the only way to be totally sure would be for your vet to do a skin test.
Mites most often first become apparent around the ears & eyes, usually but not always with scratching.
They can get mites from some natural materials like wood, hay, plant material etc or it can be the mites that normally live under their skin but can get out of control usually when something like stress has compromised the immune system.
It could also be a nutritional deficiency of some kind, evening primrose oil, flax seeds & nutritional yeast used together can help with skin problems but this won't be a cure if there's an underlying cause that's not dealt with.
Some dry skin or fur loss isn't uncommon in old age, how old is your ham?