Our chiminea is occasionally used at summer family gatherings, but is more commonly to burn wood and leaves that won't compost. I waited for the wind to blow away from neighbours before burning waxy magnolia leaves, but was startled to see that the smoke blowing across a field of stubble and chopped straw was accompanied by glowing sparks. After a brief panic a "spark arrester" made from chicken wire stuffed into the chimney proved effective.