Can you delete them from the household inventory ?
Yes and no. When I added MCCC and used the household inventory delete, there were clearly more items than were visible. (I noticed this because I was monitoring the Save size.) Which seems odd since I had originally (when playing without mods) used the show hidden and live objects cheats.
I think this is why letting the game boot my Sims to HM (instead of moving them out myself) worked to get rid of the Festival items when I uninstalled CL. When I checked to see if they were in HM after uninstalling CL, I was spammed with "item not found" messages. There was a lot of cruft hiding in their inventories.
