This is a little tip for you hardy folk who still have the patience to do BLB.
So, you send out 100 emails and one webmaster responds favourably.
Instead of removing the dead links, volunteer to find alternative sources.
As you help him fix the broken links, create an Excel spreadsheet. Three columns per tab. Record the broken url, the alternative one and the resource url (the page you're fixing).
Now, after the changes have gone live, go through the "alternative" column and collect the webmasters' contact details. Get in touch with them and tell them that
"I recently helped a pal to fix a website and I've updated his resources page. I selected your page for //insert resource page url// because //insert why you think his page is amazing//. Please let me know when you add similar content in the future...
or something like that. Also don't forget to follow them on Twitter.
If they respond (and in many cases they will), all you have to do now is pitch for a guest post or show them the extremely cool linkable asset you've built.
Also (and this will be obvious for many but I will still mention it) don't forget to go through the "broken" column and check the urls via MajesticSEO or whatever you're using for link research.
Chances are that if the initial target linked to that broken link, there will be other webmasters linking to the same page.
So, just one initial broken link has suddenly exploded into many opportunities. Yey!
Any other tips?