If it were my rig and couldn't get a replacement I would try this:
1, Look up on line for a x ray view (Often called Phantom view) of the internal layout.:
2 Remove unit.
3) Drill a starter hole where the charcoal is.
4) Expand hole to 1/2 inch.
5) Shake out all old charcoal.into a glass jar.
6) Go to Walmart pet dept and buy a bag of activated charcoal used for aquarium filters.
7) add new charcoal (the same amount as what you took out.)
8)Over the hol,e use some kind of screen mesh as a scaffold.? Use a few drops of Crazy glue to locate the screen over the hole.
9) Use some epoxy over the mesh with the old hole facing up.? So the charcoal rests below the fix.
10) After the epoxy sets, re-install the canister.
