A good reference is "Is It Kosher", by Rabbi Eliezer Eidlitz
(publisher: Feldheim 1992), head of the Kosher Information Bureau, and
endorsed by the Vaad Hakashrus of Baltimore. It has quite a lot of
information. One chapter is "Products That Do Not Require Supervision"
Some of those products are (*=additional clarification in the text):
Aluminum foil, baking powder, cocoa (plain), coffee (plain, no
flavoring), corn starch, dried fruit*, flour (plain), fruits (canned and
frozen)*, gin, guar gum, honey, molasses, maraschino cherries*, nuts*,
oats, pectin, plastic bags & wraps, popcorn kernels*, raisins, rice*,
riboflavin, rock candy*, rum, rye liquor, saccharin, sake (pure), salt,
sorbitol, soy beans, spices (pure), starch, sugar, tequila (without
worm), tea (plain)*, vegetables (fresh and frozen -- pure)*, wheat, wheat
germ*, yeast.
Additionally, there's chapters on Pesach foods, problems with
other ingredients, etc., etc. A very nice book, which I urge you to
buy.
--Mike Turniansky