Black Crusties on Comb and Wattle

[PoppySeedy]

At first I thought this might just be a bluebell thing bc my girl has had the crust since she was a young adult hen but after seeing other bluebells I don't think it is. Does anyone know what this black crust is and how to get rid of it? Would petroleum jelly help?

 

[PoppySeedy]

She looks so much worse in the photo than in real life, poor girl looks like she has a bad case of dry skin