The International Cyclopedia - New York. Dodd, Mead and Company 1887

I have a set of leather covered International Cyclopedias. They read: Brazen Circulating, entered according to act of Congress, in the year 1885, by Dodd, Mead, and Company, in the Office of The Librarian of Congress at Washington, Copyright 1880-81, by The American Book Exchange. They are well loved. I am wondering if I should tear them apart for crafting or do they hold any value.
Thanks!

By Krista