Less than 1/48th missing is still considered a whole loaf. So if you only have two challot (or other loaves of bread) for a Jewish festival, you might be able to use one loaf twice:

• Wash your hands,
• Say ha'motzi,
• Cut off a piece that is less than 1/48th of the loaf, and
• Eat it.

The blessing on matza brei is mezonot, as long as the pieces of matza are smaller than 1.3 fl. oz. (39 ml, or 1/6 cup) each. If even one of the pieces is larger than 1.3 fl. oz., wash your hands and say ha'motzi before eating it.

When washing to remove tum'a, the ideal is to pour water over your hand up to your wrist; the minimum is to pour up to the knuckles adjacent to the palms of your hands.

Exceptions On Yom Kippur and Tish'a B'Av, wash only up to your knuckles (but if you accidentally pour water further up on your hand, it is not a problem).

Non-Jews do not have ritual impurity (tum'a) the way Jews do. However:

• If a Jew touches or carries a dead non-Jew, tum'a is passed on to the Jew.
• If a Jew walks through a non-Jewish cemetery, the Jew should wash his hands the Three-Times Method.

The presence of insects on fruits, vegetables, grains, etc., depends on season, location, crop type, year, and current conditions in the growing area. If more than one bug is usually found in 10 servings, you must wash or soak (preferably in salt water or soapy water) all of the food and carefully check a quantity equal to three servings. You may check the food or the water in which the food was soaked, if such soaking will remove the bugs.
If you do not find any bugs by this procedure, you may use all of the other (uninspected) food.
If you find even one bug, you must either check each piece of vegetable OR soak (preferably in salt water or soapy water) or rinse the entire batch. Then check three more servings and continue until no bugs have been found after one cycle of washing and inspecting.

If you said a fore-blessing and ate a snack, but then decided to eat bread and a full meal:

• If your meal will not contain any foods that have the same after-blessing as your snack--
  • Say the snack's after-blessing, and then
  • Wash your hands and say ha'motzi.
• If your meal will contain foods with the same fore-blessing as your snack (even the same food as your snack)—
  • Do not say the snack's after-blessing.
  • Wash your hands and say ha'motzi.

Only leather shoes are considered to carry tum'a.

WERE BOTH FOODS LESS THAN 120° F?
YES

ARE BOTH FOODS SOLID?
YES
Status If you can separate them (there are no cracks in the meat), both foods are kosher.  Consult a rabbi.
What to Do

• If one or both of the foods were already cooked, separate them and wash with soap and water (if possible).
• If it is not possible to separate them, just cut off the thinnest slice possible from each surface of each food which had been in contact with the opposite gender food and you may use the food.

NO
SOLID FOOD FALLS INTO LIQUID FOOD OR LIQUID FOOD FALLS ONTO SOLID FOOD
Status If both foods are cold and you can separate them (there are no cracks in the meat), they MAY be kosher.  Consult a rabbi.
 

• Both foods are non-kosher if they cannot be separated.
• If you can separate them enough that one becomes less than 1/60th the volume of the other:
  • The larger food is kosher.
  • The lesser one is non-kosher. 

What To Do

• Once the two foods are separated, wash or otherwise remove the smaller food from the larger one.
• If not possible, cut off the thinnest slice possible and you may eat the remaining food.

Note If there are cracks in raw or cooked meat, and if you can clean off enough of the dairy spill so that the remainder is less than 1/60th, it may be kosher--ask a rabbi.
 
LIQUID FOOD FALLS INTO LIQUID FOOD
Status Both liquid foods are non-kosher.
Exception If one liquid food is less than 1/60th the volume of the other one, the mixture is kosher.
Note If non-kosher wine is involved, see below.
 
SOLID FOODS, ONE OR BOTH ARE HOT
Status If one (or both) of the foods is hotter than 120° F, both foods are non-kosher.
Exception If one food is less than 1/60th of the volume of the other:

• The larger-volume food may be kosher (consult a rabbi).
• The smaller-volume food remains not kosher.

Possible Exception  If the food on the bottom is cold and thick, consult a rabbi.

If either food is spicy, see above.
If any combination (solid and liquid; solid and solid which are in any liquid; or liquid and liquid) of dairy and meat were soaked together for 24 hours or more, even if cold, they are all not kosher.
Exception In any of these three cases, in which one is less than 1/60th the volume of the other:

• The larger food is kosher.
• The lesser one is non-kosher.

Note You must remove the smaller food from the larger one and wash off the larger one, if possible. If you don't know how long the foods soaked together but it may have been less than 24 hours, you may use the foods.
 

Situation

You wake up after sleeping for more than 30 minutes and need to say a blessing immediately or else you might lose the opportunity to do so.

What To Do

Even though you have not washed your hands after sleep, you should say the blessing.

Example

Situation

You are in bed and hear thunder.

What To Do

You should immediately say kocho u'gvurato even though you did not wash your hands (but you should quickly rub your hands on cloth or clothing first). If you then see lightning, you say oseh ma'aseh vreishit.

Say birkat ha'mazon instead of al ha'michya if you ate enough bread-like foods (mezonot) or bread-like food combinations (such as crackers with tuna salad) to be the volume of your normal biggest meal of the day. This is true even if:

• You had not planned to have a meal (for example, you planned to eat only one slice of pizza but then ate two more), and
• Did not wash your hands before the meal.