Find a large saucepan or pot that can contain the starter jar for sourdough or anything else. Place the jar in the pot to test the size. Fill up the pot with water and bring to a rolling boil; it should have large air bubbles bubbling up from the bottom.
Using rubber gloves or kitchen tongs, pick up the jar and submerge it in the boiling water for 5 minutes. Also drop in the spoon that you'll use for stirring.
Remove jar and spoon after 5 minutes and place on clean kitchen towel. (Don't place them on a dirty kitchen counter; your sterilized tools will no longer be sterile. Placing the spoon in the jar is a good way to avoid this.)
Allow them to cool for a few minutes while you collect the other ingredients.
ANOTHER WAY: Put the utensils, etc. into
the microwave for 2 minutes on high. Remove with hot pads -- they are extremely
hot !!