The develop module menu bar: Develop>Clear History. This will clear the entire editing history of the image but will not reset or change the edited image. I don't know of a way to clear only a portion of the edits.Is there a way to delete some of my History steps so that he History Tab is not so populated with steps etc.?
I'm not sure why you would want to do this as the edit information takes-up very little storage space compared to the image itself. If it's simply to remove visual clutter, I leave the entire left side panel hidden in Develop (I rarely use it) to free-up more image space. Same with the grid view - I leave the right side panel hidden.
~ Peter