I've used quite a few bags of Cowboy, mostly to get the offset fired up. While bags from years past did indeed contain furniture scraps, if the furniture was being made from good charcoal-producing wood I see no reason to find the practice suspect, by itself.
My bags didn't really contain any more way-too-small pieces than any other brands used, including "premium' ones, and a couple even housed small logs of charcoal that had to be broken up with a hammer.
The thing that we found less than desirable with Cowboy was the relatively short burn duration of the lump, when compared to many others.
All in all it did it's job, even if having a short burn time. When it is on sale for a great price it is still worth it.
Oh, and we've found foreign material in just about every "premium" brand of lump charcoal out there: I believe it is a result of the basic manufacturing methods common to most lump companies. Since we always sift through the lump a bit as it is poured into the cooker, it has never been a problem, regardless of brand.