Cleansing of Tools
Consecration rituals are generally quite straight forward and it is nice to construct your own.  The best way is to dedicate the tool to spirit and ask that it be cleansed and consecrated for the good of all.  You can make up a short invocation to dedicate the tool to its purpose and any particular Deity or element.

Below I have posted some examples which I think are rather nice:

Consecration of Tools
(From "Wicca: A Guide for the Solitary Practitioner" by Scott Cunningham)

Light the candles on your altar and burn some incense.  Cast the circle.  Place the tool to be consecrated on a pentacle or a plate of salt.  Touch it with the point of the athame (or your projective hand) and say:

"I consecrate you, O knife of steel (or wand of wood etc) to cleanse and purify you to serve me within the Circle of Stones.  In the names of the Mother Goddess and the Father God, you are consecrated."

Imagine energy flowing into the tool, cleansing it of all negativity and past associations.  Now pick it up and sprinkle with salt, pass through the incense smoke, through the candle flame and sprinkle with water, calling upon the spirits of the stones to consecrate it.
Then hold the tool to the sky saying:

"I charge you by the Old Ones: By the omnipotent Goddess and God: By the virtues of the Sun, Moon and Stars: By the powers of the Earth, Air, Fire and Water, that I shall obtain all that I desire through you.  Charge this by your power, Old Ones!"

The tool should immediately be put to use to strengthen and bind the consecration.  E.g. the athame can be used to consecrate another tool; a wand to invoke the Goddess; the pentacle to act as a resting place for a tool during it's consecration.

Consecration of Candles
(from "Earth Magic" by Marion Weinstein)

Before a candle is used in ritual it should be consecrated by the Witch.  As you light each candle for the first time say:

"The One Power
Which is Goddess and God,
Works for and through me (your name), a perfect microcosm of the power,
And I consecrate this candle to the use of Positive work only,
For the good of all,
And according to free will.
And so mote it be."

Consecration of Tools 2
(from "Everyday Magic" by Dorothy Morrison.)

1 white candle
1 bowl of water
Frankincense or Sandalwood Incense
1 small dish of soil

Light the candle and the incense.  Pass the tool through the incense and smoke and chant:

"I cleanse you with the breathe of air,
Winds blown cold and winds blown fair"

Pass the tool through the candle flame and chant:

"I cleanse you with the warmth of fire,
Dancing flame and purifier"

Sprinkle the tool with water and chant:

"With water I cleanse and give you life,
Babbling brook and surging knife."

Sprinkle the tool with soil and chant:

"I cleanse you with the depths of earth,
Home of death and place of birth."

Take the tool in both hands and lift it skywards, and say:

"Be free of negativity,
As I will so mote it be."