As long as you have the right leather, making the strop shouldn't be a problem. If i were you, I'd still try to remove as much abrasive from that pasted strop as possible and switch over to a finer finishing abrasive like 1.0, 0.50 or 0.25 micron diamond or chromium oxide.
I'd start with saddle soap and probably sand a layer off the top before washing it out with more saddle soap.