I've mentioned my fantastic Squeezo-style food strainer a couple times already (here and here). If you do a lot of canning (especially tomato sauce, pumpkin puree, or applesauce) you have to get one of these gadgets. I recently used my Roma Food Strainer to make tomato puree for canning spaghetti sauce.
Load the hopper full of roughly hacked up tomatoes (I mostly just cut them in half so they wouldn't explode al over the place when they get pulled into the grinder) skins on, stems on, gross corky cracked parts and all.
Out one end come the skins, cores, stems and seeds.
I passed the waste material through the strainer an extra time to get a bit more pulp out.
Out the other end comes the tomato pulp, perfectly pureed and seedless.
Making tomato puree using the food strainer was a lot easier and faster than the way I used to do it (core the tomatoes, plunge into boiling water, plunge into ice bath, remove skins, chop up, puree in blender). Hopefully I'll be willing to make a few extra batched of sauce this year since it's so easy.