Tevila is the Hebrew word for immersion.  You must tovel (immerse in a mikva or other halachically purifying water) new utensils made of metal or other materials that require tevila unless you know that they were:

• Made by a Jew,
• Sold by a Jew, and
• Not owned by a non-Jew in between.

Toveling: Utensils: How To Tovel
To tovel a utensil, you may go to any kosher natural mikva (see section on natural mikvas) or to a mikvat keilim (a small mikva for utensils, often attached to the outside of a regular mikva building). To tovel several items, some of which require a blessing and some on which there is doubt whether a blessing is necessary, say the blessing over the item that requires the blessing and have in mind that the blessing will cover all the rest of your items.
Remember to remove all stickers, rust, etc., before you begin. Nail polish remover may help with stubborn stickers. Say the blessing al tevilat keilim and then let the item free fall through the water. Unlike with hagala, during which the item may be immersed in sections, when you tovel a utensil, the entire item must be in contact with the water at the same time, even if only for an instant.

Toveling: Utensils: What Gets Toveled?
The below chart is copied with permission from the Star-K (www.star-k.org):
 
 

Utensil	Tevila Guideline		Utensil	Tevila Guideline
Aluminum Pans, Disposable if intended to be used more than once	Tevila with Brocha		Meat Tenderizer Hammer, Metal	No Tevila
Aluminum Pans, Disposable to be used only once	Tevila w/o Brocha		Melamine	No Tevila
Blech	No Tevila		Metal Cutlery	Tevila with Brocha
Blender with metal blade on bottom	Tevila with Brocha		Metal Flour and Sugar Storage Canisters	Tevila w/o Brocha
Bone	No Tevila		Metal Pots Coated with Teflon, Enamel or Plastic	Tevila w/o Brocha
Brush, Pastry	No Tevila		Metal Spoon Specifically for Medicine	Tevila w/o Brocha
Brush for Grill, Metal	No Tevila		Microwave Turntable, Glass	Tevila w/o Brocha
Can Opener	No Tevila		Mixer Beaters	Tevila w/o Brocha
Cans, Reusable Empty if opened by a Yehudi	No Tevila		Paper	No Tevila
China, Bone	Tevila w/o Brocha		Peeler, Vegetable	Tevila with Brocha
China, Glazed	Tevila w/o Brocha		Plastic	No Tevila
Colander, Metal	Tevila with Brocha		Porcelain Enamel	Tevila w/o Brocha
Cookie Cutters, Metal	No Tevila		Racks, Cooling	Tevila w/o Brocha
Cookie Sheets, Metal	Tevila with Brocha		Racks, Oven	No Tevila
Cork Screw	No Tevila		Rolling Pins Metal or Wood	No Tevila
Corningware	Tevila w/o Brocha		Sandwich Maker	Tevila with Brocha
Crockpot Ceramic Insert	Tevila w/o Brocha		Silicone	No Tevila
Crockpot Glass Lid	Tevila w/o Brocha		Sink Racks, Stainless Steel	No Tevila
Crockpot Outside Metal Shell	No Tevila		Spatula, Metal	Tevila with Brocha
Dish Rack, Metal	No Tevila		Stoneware	Tevila w/o Brocha
Dishes, Ceramic	Tevila w/o Brocha		Stoneware, Non-Glazed	No Tevila
Earthenware, Non-Glazed Dull Finish, e.g. Flower Pot	No Tevila		Storage Utensils, Glass not brought to the table	No Tevila
George Foreman Grill	Tevila w/o Brocha		Styrofoam	No Tevila
Glass (including Pyrex, Duralex & Corelle)	Tevila with Brocha		Tea Kettle, Corelle	Tevila with Brocha
Grater, Metal used for foods that are ready to eat, eg, apples, onions	Tevila with Brocha		Toaster which will not break	Tevila w/o Brocha
Grater, Metal used only for foods that need further cooking,eg potatos	Tevila w/o Brocha		Toaster Oven rack & tray only	Tevila with Brocha
Hamburger Maker	Tevila with Brocha		Trivet, Metal	No Tevila
Hot Air Popcorn Maker, Metal	Tevila with Brocha		Waffle Iron	Tevila with Brocha
Hot Water Urn, Metal	Tevila with Brocha		Warming Tray	No Tevila
Knife, Arts & Crafts	No Tevila		Wood	No Tevila
Knife Sharpener	No Tevila		Wooden Cask with Metal Straps	Tevila w/o Brocha
Meat Thermometer	No Tevila

When toveling a utensil that is partly made of metal (which requires tevila) and partly made of plastic, wood, or another material that does not require tevila, you must dip all parts of the utensil into the mikva, even the parts that would not require tevila on their own.

If you have a non-kosher food utensil, kasher it before you immerse it in a mikva (tevila).
 

Before immersing a food utensil in a mikva, remove anything attached to its surfaces.
Situation A sticker or something similar is found on a plate or other utensil after tevila.
What to Do

• Unwrap the excess strap from your palm and wrap it three times around your middle finger while saying the three “v'eirastich li” phrases, one for each wrap.
• Wrap the strap around your palm in the shape of the Hebrew letter “shin.”
• Wrap the excess around your palm and tuck in the end of the strap to keep it tight and out of your way.

1. Place the tefila on your head tightly enough so it does not slip off under normal motion.
2. Center the head tefila box on your forehead (as it appears to an average person. There is no need to look in a mirror.)
3. Place the head tefila box with its front edge above your hairline (or where your hairline was when you were 13!), not further back than half-way on your skull from front to back.
4. Ideally, place the knot at the back on your occipital bone (base of your skull), but you may place it lower as long as it is still on top of your hair.
5. Say the second blessing, al mitzvat tefilin.
6. Tighten the tefila on your head and say, Baruch shem kevod malchuto l'olam va'ed
   Reason “Al mitzvat tefilin” is a questionable blessing (safek bracha).
   Note Tefilin head straps should reach at least to your navel (left strap) and mila (right strap).

1. Place arm tefila box (bayit) on center of bicep of whichever arm you do not write with (knot on the arm tefila should touch the side of the box). If you are ambidextrous, put the tefila on your left arm.
2. Say the first blessing, “lehaniach tefilin.”
3. Tighten the strap.
4. Wrap the strap around your arm seven times between your cubit (inside of your arm, opposite the elbow) and your wrist.
   Note If you wrap more times, it is OK.
   Note You may wrap the tefilin strap over a wristwatch or put a watch on top of the tefilin strap.
   Note Tefilin straps should not overlap with each other and should not be wrapped on top of the ulna protuberance, but if they do--it is permitted.
5. Wrap the excess around the palm of your hand (tuck in the end to keep it tight and out of the way).

Say al netilat yadayim even if you wash your hands by immersing them in a river, ocean, or other natural body of water.

If you inadvertently put the arm tefila (tefila shel yad) into the box for the tefila shel rosh, take it out and put it into its proper box.

The box for holding the head tefila (tefila shel rosh) has a higher level of holiness than does the box for holding the arm tefila (tefila shel yad). You may not intentionally switch the boxes.

Put tefilin into its bag so that the knot on the arm tefila (tefila shel yad”) faces away from the head tefila (tefila shel rosh).

If a disposable aluminum pan will be used once, tovel it without a blessing. If a disposable aluminum pan will be used more than once, tovel it with a blessing (al tevilat keilim). Even if you will line it with a double layer of foil, still tovel it.

If you have finished the amida's yihiyu l'ratzon(but have not yet finished the segment from Elohai netzur through u'chshanim kadmoniyot), you may reply to:

• Bar'chu,
• Kedusha,
• Amen to ha'el ha'kadosh,
• Amen to shomei'a tefila,
• Modim anachnu lach (just those 3 words),
• Birkat cohanim, and
• Kaddish.

However, you may not say anything else (such as other amens) until you have completed the entire amida (including the last word, kadmoniot).
 

If you take off your tefilin because you have to, such as to go to the bathroom, or if one or both of the tefilin fall or slide off your arm or head, say: 

• Both blessings again when you replace the head tefila (tefila shel rosh) on your head.
• Only the first blessing when replacing the arm tefila (tefila shel yad) on your arm.
• Each blessing in its correct place if you took off both.