OK. If you really want the complicated details, This is from a site I found:
"While many Jews adhere to the same rules for buying Passover foods before and during the holiday, Jewish Law actually draws an important distinction. Certain leniencies are permitted for some foods if they are produced before Passover begins. Still other foods must adhere to the same standard irrespective of when they are produced. The following guidelines, prepared by the Conservative Movement’s Committee on Law and Standards, clarify these possibilities:
Leavened bread, cakes, biscuits, crackers, cereals, coffee ‘‘blends’’, wheat, barley, oats, rice, dry peas, dry beans, and all liquids which contain ingredients or flavors made from grain alcohol or vinegar (other than cider vinegar). For Ashkenazi Jews (which I believe all of us that will be attending are), the tradition is not to eat peas, corn, rice, beans or other legumes, because their flour closely resembles hametz; string beans are permitted.
1. The following foods require no "Kosher for Passover’’ label if purchased prior to Passover: Unopened packages or containers of coffee (plain, not blends), pure white sugar, plain tea bags, salt (uniodized), pepper, pure spices, frozen fruit juices with no additives, honey, frozen (uncooked) vegetables (except legumes, as above), milk, butter, cottage cheese, cream cheese, fresh fruit and vegetables, kosher meat and poultry (fresh and frozen) and fish, baking soda, frozen (uncooked) fruit (with no additives), ripened cheeses (such as cheddar, muenster and Camembert), baking soda, 100% pure saccharin tablets.
2. The following foods require no "Kosher for Passover" label if purchased before or during Pesah: Fresh fruits and vegetables (for legumes, see above), eggs, fresh meat and fresh fish, as well as all detergents, cleansers and scouring powders that are certified kosher year-round.
3. The following foods require a "Kosher for Passover" label if purchased before or during Pesah: All baked products (matzah, cakes, matzah flour, farfel, matzah meal and any products containing matzah), canned or bottled fruit juices (which are often clarified with legumes), canned tuna (since tuna, even when packed in water, has often been processed in vegetable broth and/or hydrolyzed protein; however, if it is known that the tuna is packed exclusively in water, without any additional ingredients or additives, it may be purchased without a kosher for Passover label), wine, vinegar, liquor, oils, dried fruits, candy, chocolate milk, ice cream, yogurt, soda."
Fun, right? I guess it's still better than being slaves in Egypt...(and um disregard the reference in the number 3 to a certain grape product)