Thank you for contacting us! It looks as if you have [describe the topics/scope of their collection]. To find the right place to donate, you would need to locate a library that specializes in collecting those topics. Though these aren’t subjects in which Pacific normally collects historic material, you might be able to find another library that does. [Name specific library/ies] might be a possibility. You would probably want to contact their “special collections” department:
[Contact info for other library's special collections department]
If you want to get an idea of the monetary value of your books, I would recommend looking them up in the AbeBooks.com site. This is a site where rare book dealers from across the United States list their books, so you would be able to see what dealers are listing your books for. (Keep in mind though that the prices you see on that site are retail prices; what you would be likely to get if you sold them to a dealer would probably be a fraction of the retail value.)
http://www.abebooks.com/servlet/SearchEntry?cm_sp=TopNav-_-Advs-_-Advs : Use the advanced search and put in a word or two from the title, the author’s last name, and a date range near the publication date of your books.
To look into selling your books, you could contact the Rare Book Room at Powell’s or perhaps another local books store that carries used books. For a general looks at what makes a book rare and how valuations are done, here is a great pamphlet: http://www.rbms.info/publications/your_old_books_compact/YourOldBooksCompact2.pdf