Prepare pumpkin by peeling, cubing and discarding seeds and inner
pulp. Place pumpkin cubes in colander and set over boiling water.
Make sure water does not touch pumpkin. Cover and steam until just
tender, 5 to 7 minutes. Drain.
Simmer vinegar, sugar and cinnamon for 15 minutes.
Add pumpkin and simmer 3 minutes. Set aside for 24 hours.
Heat and simmer 5 minutes more.
Remove cinnamon sticks. Pack boiling
hot in hot canning jars, leaving 1/2-inch headroom.
Adjust lids and process in hot water bath for 10 minutes.