Gold on the bookshelf

A friend has recently discovered this site.
She regularly trawls the charity shops for old books, especially on fantasy and sci fi.
She's now decided to sell some on this site to boost her income a little. I did a quick check from my own bookshelves. Most gut wrenching discovery was that a two volume set of botany books inherited from my grandfather would be worth £800, sadly I only have one volume as the other was destroyed in a house flood we had many years ago.
I'd have kept it, but "helpers" at the time threw it out. Of course I didn't know it's value and thereore didn't claim it on my insurance. Oh well it's only money............