How do I remove items (individual or all) from Reading List on my iMac (OS X 10.6.8)?
I'm running OS 10.9.x right now, but I don't think it should be too different. When you open the reading list by clicking the little glasses (I think that's what it was- it may be under the same book icon as bookmarks), mouseover the item you want to delete, and you should see a tiny x in a circle appear in the top left of that item. Click to delete it.
sidebar for reading list, has a tiny x to remove that one item
control-click it to get an option for delete all
found on https://discussions.apple.com/message/24035730#24035730