NetLogo BehaviorSpace Slows after several experiments

Question

I am using BehaviorSpace. At first it worked great, completing 80 runs in less than one hour. After doing about 10 different experiments in BehaviorSpace, it is now running at a considerably slower rate (almost to a halt), and now I am getting an error of "out of memory". I use clear-all as the first command in my setup procedure, but it seems like NetLogo is holding some memory over from previous runs. I have tried switching to table output, and disabled spreadsheet output, but still got an out of memory error. I see several posts on BehaviorSpace memory issues, but I cannot seem to figure out why the models ran so quickly to start, and now hardly runs. I am using NetLogo 5.0.5 on a server with 16 cores and 64 GB of RAM, and have models running in parallel. Does anyone have an idea where this memory is being tied up, and how I can clear it?