Tomato seeds are likely to pass through holes larger than 2 mm. The coarse (larger hole) discs are better for making pizza sauce and salsa.
Electric mills are a wonderful convenience, especially for those who have arthritis or who prefer operating the mill with only one hand. Though we do not sell them on this web site, a number of heavy duty models are available in our Philadelphia store.
The Roma is a real time saver when you're working with large quantities of food. Wash the screen often, so the holes don't become obstructed by the smaller seeds.
Remember to blanch or boil foods before using a food mill. The food must be soft enough to go through the holes. Check out 75 Ways to Use the Foley Food Mill, with information from about half a century ago that is still quite useful.
Removable conical discs must be inserted with the cone-end up.
Clean your food mill often, so that it can work unhampered by seeds and skins. All food mills come apart for easy cleaning.
DO NOT crank the handle (or turn the power on) without foodstuffs in the mill; running it dry makes it difficult to crank and will cause the scraping metal parts to scratch the surface. Once you add foodstuffs, the liquids and pulp create a barrier that prevents scraping, and make cranking the food mill easy. (Keep in mind the special care required for utensils and parts made of Tinned Steel.)