A mouli, also known as a food mill or sieve, remains strongly associated with classic French cooking and Julia Child -- so much so that one is on exhibit in the Smithsonian museum re-creation of Child's kitchen. Using one is quite straightforward -- you set up the blade and twirl a handle, much like a horizontal version of a flour sifter.
Where moulis shine compared to food processors is in pureeing tomatoes, berries and fruits, because the mill captures skins, seeds and thicker pulp, and the blades press through only the puree.
Select the proper blade for your planned milling. Use the fine blade for baby food or sauces, the fine or medium blade for applesauce, the medium disc for vegetable soups, and the medium or coarse blade for mashed potatoes.
For berries, select a disc depending on whether you want preserves, jellies or jams of a fine, medium or coarse texture.
Turn the blade disc so that its domed side points upward. Drop the disc into the mill, following the manufacturer's instructions. It may simply drop in so a center hole aligns with a pin, or you may have to also align a notch in the disc with a groove in the mill.
Align the pin at the bottom of the pusher post with the center hole in the disc and drop it in place. Align each end of the crossbar of the pusher under the tabs under the rim of the mill. The crossbar may have slots that hook under the tab.
Open the nonslip legs, if present, to allow the mill to sit solidly atop a container.
Cook the fruits or vegetables you plan to mill, and allow them to cool.
Place the assembled mouli over a large measuring cup or bowl. Pour in your tomatoes, potatoes or other ingredients.
Rotate the handle clockwise for several turns as the mash or puree drops into the bowl. Reverse direction periodically to avoid clogs. Continue until only coarser material rests in the mill.
Change discs or disassemble the mouli by pulling back on the release button on the crossbar and lifting it out of the way. Swap the disc for another.
Disassemble the mouli. Carefully wash its components -- pusher, mill and blade -- by hand, or place it in the dishwasher if the instructions note this is safe.
To save time and effort, you can leave fruits and vegetables -- other than potatoes -- whole even if you plan to cook them before milling. For potatoes, peel before or after boiling.