I have come to realize that I still own partially used soaps purchased back in 2014. That annoys me a bit, honestly. ...
I think you are doing great if those are the oldest soaps in your inventory! I recently finished pucks of Tabac and MWF that I purchased on B/S/T in 2009, and I still have some other soaps acquired in 2011.
My personal record, however, is a puck of Old Spice that I purchased sometime in the early 1970s that I finished off in about 2010.