I use wooden clothes pegs, and my clothes line is under cover, so its not like they are always out in the weather or anything (I even take them off the line when not in use), but they look mouldy/mildewy (tbh, I don't know what the difference is) where they come into contact with the clothes.

Can anyone tell me why? And I guess more importantly, is this a health issue? What can I clean them with, if anything?