If the paper has been stuck down with paste or glue, bookbinding and paper conservation specialist Riley Dunn & Wilson says the easiest way to remove it is to dampen the paper with a wet sponge.
Repeat regularly until the paper becomes loose then prise it off carefully.
If the main board is detached from the book, you can also immerse it in water.
If the bookplate is stuck on to paper rather than board, repeat the same process but use blotting paper to ensure the dampness doesn’t seep through to other pages.
Riley Dunn & Wilson would be delighted to help. Contact the company at Almond Court, Falkirk, Stirlingshire, tel 01324 621591.