Hi Vanes and welcome to GoY, are these the old leaves from this year? They do end up looking very scruffy and we cut them off. Can you add a photo to your question so we can see the problem.

The best way to keep Hellebore foliage clean is to cut off every old leaf in early winter. The streaks are Hellebore leaf spot and are caused by a fungal infection. They need tidying up every year right down to the base or they infect the new leaves. Also if any of the flower shoots get black parts cut them off too. It's all a matter of hygeine, but easy to keep on top of.