As you walk down the aisles of your supermarket, you may notice the words "Kosher for Passover" on some items and wonder what it actually means. Most people know that Jews eat matzoh instead of bread during Passover—but why would some soda, candy, or even vegetables be kosher for Passover while others would not?

Here is some information that should make things a little clearer.

During Passover, Jews refrain from eating chometz: anything that contains barley, wheat, rye, oats, and spelt, and is not cooked within 18 minutes after coming in contact with water. No leavening is allowed. This signifies the fact that the Hebrews had no time to let their bread rise as they made a hurried escape from Egypt.

Jews of different backgrounds do not observe all of the same rules. Ashkenazi Jews, who come from Europe (most Jews in America), also avoid corn, rice, peanuts, and legumes as they are also used to make bread and may have other grains mixed in. These items are known as kitniyot.

Rules and guidelines may be extremely stringent. Not only must Orthodox Jews not eat these items, but they also must completely remove them and any food that has come in contact with them from their homes. They may throw them away, burn them, or sell them to a non-Jew (they are allowed to buy them back at the end of Passover). Some go through amazingly thorough and labor-intensive cleaning processes to rid their homes of any hint of chometz or kitniyot. For example:

Sinks, refrigerators, ovens, and stoves must be scoured and then not used for at least 24 hours before the beginning of Passover. Specific Passover china must be used.

Silverware must be "heated to a glow" and then cooled. Items are placed in a pot of boiling water (usually one at a time, because they must not touch each other during the process) and then immediately submerged in cold water.

Pots must be cleaned inside and out. To accomplish this, a pot must be filled with water and brought to a boil. Then to clean the outside, a brick or rock is placed inside to cause the boiling water to flow over the sides. However, said rock must be hot because the water must still be boiling as it cascades over the sides. A cool rock would cool the water when it came in contact. A blowtorch can be used if one is available.

Items which seem acceptable for Passover but may not be:

Soda: Most sodas contain corn syrup. Since eating corn is a no-no, soda containing corn syrup is also out. Even if corn syrup is not used, sodas generally have "additional flavorings" which are not divulged and could be derived from grains. Only sodas produced under supervision of a rabbi or other official certified agencies are acceptable.

Frozen vegetables: Many bags of frozen vegetables are produced on the same machinery that also produces pasta or pasta/vegetable blends. Since pasta is made from grain and not allowed, neither are most frozen vegetables, unless made under supervision.

Raw vegetables: Some fruits and vegetables (cucumbers for example) have wax coatings that may be made from soy proteins and oils derived from grain. Sorry, no dice.

Dried fruits: These are often dried in ovens where bread is sometimes baked. Some also have waxes, oils, and even traces of flour to prevent sticking.

Marshmallows: Not allowed unless made under supervision. They contain gelatin, which is made from the bones of potentially non-kosher animals.

Milk: Unsuitable additives are often used. Chocolate milk is usually unacceptable because it could contain corn syrup or malt, which is made from grain.

And these are just food items. Balloons and rubber gloves can have a powdered coating on them, which may be considered chometz. Even some bug traps use an oatmeal or wheat-based substance and must be removed from the premises.

And let's not even get started on pet food.