If you shake the dead flower heads over a seed tray with a little compost mixed with sand and a cover of grit, then put them somewhere safe - I left mine outside the greenhouse for a few months
. They do not like to get too wet - just slightly damp is plenty, so in the greenhouse if you do not live in the arid wastes of east Anglia.
I used to have a self cleaning gas oven but had to clean the glass door. My latest fancy self-cleaning one is far from it
and I really hate cleaning ovens. In fact to get the door properly clean it needs dismantling
My grandma used to smear the inside of hers with a paste of bicarb and water after she cleaned it. It looks awful, but the brown stuff just wipes off next time you clean it. I do that too, but I still can't summon up the will to clean it.