These labels are made from a strong plastic and are reusable for many years. We find that they are best used with a soft type of pencil, a 2b is ideal. If you use a pencil then you can either wash clean or simply rub with a piece of perlite to clean off the writing instantly. We find that if you use a permanent marker pen then you cannot reuse again the following year or if it is for longer term them the sun gradually fades the ink and so no use to man or beast, this is why we use a pencil. Once you feel that the labels have become unusable after many years in the sun then they can be recycled.