Sun can cause damage to curtains, particularly those hung in south or south-west facing rooms where they are exposed to many hours of strong afternoon and evening sunshine. You should be aware that the sun can bleach fabric, stripping it of colour, and this will be most noticeable on the leading edge of the curtain. Dry Cleaning won't restore the colour, but we would recommend that you re-hang the left curtain on the right and the right on the left so that the original leading edge is very much less obvious back against the wall.