I just sold 75 pounds of recycled assorted Legos in the last 2 weeks, and most of a complex mechanical set. The set was a terror to take apart...
I also went through all of them to extract every minifigure and accessory part to sell separately. There was lots of neck fatigue from looking down for so long at the pieces. I felt your pain. Now I just have to finish building out, dressing up and weaponizing about 75 minifigs...
RE: Near death experience and my home-made solution