Sounds like these are rather small servers. I have done many larger ones with much better returns. As Olddude mentioned 50-60 cents/lb should be easy to attain.
Just scrapped 4 Compaq servers about 100 lbs each, the 4 yielded a total of 50 lbs of high grade boards, 10 lbs clean slot CPU's, 5-6 lbs RAM, etc. I can easily make $30-40+/hour breaking down servers. I also have done a few really big units 1000-1200 lbs each, those make a LOT more $$$!