A while back I made some "pipe mortar", I had put it on a cob & a small pipe.
Over time, I ended up not really smoking them, as I gained other pipes after. The mortar is now fully dry, and is easily damaged, crumbling at any fair touch.
I do not know if smoking them will do any good for the mortar, but from seeing other's posts from across the web which I've now found, I doubt it would help.
Its not all loss, as I can easily just replace the mortar with real pipe mud, it would be very easy to clean out.

I have, however, now tried another idea, which is to use plaster of paris & wood glue to make pipe mud.
I didn't follow the recipe I saw fully, just winged it, but its a $10 pipe, so whatever.