You don't have individual recipes on your Bookshelf (apart from online recipes you have added one-by-one) but books, magazines and blogs. If we allowed members to add each individual recipe then the site would run much slower - for every member, no matter how much they had on their Bookshelf. So you cannot delete individual recipes from books, magazines and blogs since that is not how they are stored.
I suggest you approach this the other way round and bookmark the recipes you are interested in so when you search you can filter just to those recipes you know you like. Then if you don't find what you want, you remove the filter and search your entire Bookshelf (your archive in your scenario).
Since we added the 'I've Cooked This' and 'I Want to Cook This' bookmarks I have started going through my own books, adding those bookmarks. This means I will be able to reduce my search results initially to a more manageable number.