To remove the cat to clean:I assume you meant "once" Now I'm really confused. Are early Progress stoves cats hard to get at? Are they different? Mine comes out in about 30 seconds no tools. IF you are attempting to clean it #1 by sucking with a vac and #2 not taking it out that's a no go.
1. carefully remove 3 soapstone top pieces, lay aside
2. remove gasket around metal plate
3. remove metal plate
4. remove gasket around cat
5. remove cat
If you can do that in 30 seconds, you're better than I.
I do not attempt to clean the cat in place. That would involve trying to suck the dust through the cat.