Knowing the challenges I  face with kiln firing flexibility,  my designer-metalworker son is treating me  for my 84th birthday to an entire day  with a friend's raku kiln  and firing my primitive kilns at his workshop   (Then his wife and the grandkids will join us for pizza in the new steel brick pizza oven he designed...this potter's dream birthday.)    I want  to build at least one  mini primitive kiln before the 14th,  since my last kiln  sadly had its last firing in CT at my other son's home and will become  a  ceramic  waste pile for future archaeologists there.    Hay is sort of messy and a pain to chop up  in a communal studio, and I'm wondering if other sources of cellulose might work.  What about sawdust if I can't find things like  pine needles or leaves on "campus" here?   Paper from a shredder?  It might be fun to try old coffee grounds, as the aroma during the firing would be rather pleasant!    I plan on  reconstituting some scrap sculpture clay adding vermiculite to  lighten it, but I also want the tensile strength given by the hay.  No time for  experiments this time and no car  to use for venturing far afield for materials,  so I again  seek suggestions from  the Clay Art  community.  Cheers, all,  Carolyn