Toby Barclay is 100% right though there is a more friendly version. They do produce a clean removable washable and water soluble type of PVA. On this side of the pond it is sold as preschool or children's PVA adhesive. It has enough grip for case labels and easily reversible leaving no marks or stains if you dont want to go with the Rabbit skin glue that was the Victorians go to adhesive for any high quality paper fixing.

The only lessons in my life I truly did learn from where the ones I paid for!