So I'm going to guess launching a new domain isn't an option?
You can use Excel to segment the linking root domains (LRDs) by those that are probably directories - those that contain terms like "directory", "URL" and "submit" in the domain. There are a couple of ways to do it but just as an exmaple if you enter the following into Excel it will tell you whether the URL in A2 contains the term "directory".
=isnumber(search("directory",A2))
It pays to scan over these links and see if there are any decent sites that you've bundled in with the bad but mostly I'd imagine they will just be directories.
You can do the same thing with adult terminology to find those types of sites. The method is by no means perfect but it is quick and easy.
Possibly the easiest way to spot low quality links is looking at the C-block. If you've got 50 links from the same C class IP then it's either a bad link network or a blog service. You'll spot the difference pretty quickly although if you have several clients wanting this service then it might be worth excluding the IP ranges of the major blog services in your spread sheet. I don't think you can currently get IP from OSE but I'm sure you'll figure out a way.
That's all that I can think of off the top of my head but I'll add more if I think of them.