This should help. I believe this is what they mean. I had created and had been tweaking a large object and along the way things started to get very slow. So, once I had reached a point where things were starting to get slow, I simply exported the object as an STL. Once that was done, I simply re-imported that STL file back into a new design panel. I did this with any other objects in my previous design that I did not want history for. For those objects that I did want history, I simply Copied and Pasted them from my old design, into my new design. Wow, was it ever nice to lose all that history. Perhaps a parameter that limits the number of changes might be nice. Good luck and keep Tinkering.