I thought I might be able to make them disappear a little if I painted them white. I used some watered down white acrylic paint topped with some water-based estapol. The estapol knocks back the white to a very soft white which I like a lot. I have used this method with picture frames in the past. I was really happy with the wooden frames, but the painted cork didn't look quite so good. So I thought about it a lot and decided to staple some fabric over the cork. Don't ask me why, but I needed to think about it for a week before I did it. It seemed very scary! Today (Monday) I covered the first board. It was easy. (Why do I worry so much?) I am very happy with the result.
Progress in my sewing room is very slow, but I'll get there!