Sometimes, tools, crystals, or other things you use need to be cleansed of all the energy it picked up from being used or the like. Note: Most elemental cleansing methods can also be used to charge items, especially crystals, with that element. Here are some ways to go about doing it if need be.

Smudge Method
Simply use the smudge guide (found here) and smudge the item for however long feels right. If it is porous (such as wood), the smell may stick to it, so be careful. If you do not want it smelling of smoke after, try the water method.

Water Method
Warning: Some types of crystals (See list here) will either break apart, dissolve, or can even be toxic if exposed to water. If you choose to do a salt water method, the salt can also damage porous rocks. Please be careful if you choose this method and research which crystal you have. Also, this method may not work well with wood or certain metals.
To do this method, you will need water of course. Some people prefer natural sources (Rain, Streams, Rivers, Lake/Ocean Waves, etc.), while others prefer just plain old water from the tap. Whatever works best for you should be fine, but natural sources are much better for charging. Simply submerge your item in water and let it soak up unwanted energy. If you use streams or other natural sources, let the water wash over it. Do this for however long feels necessary. If you want to use salt as an added purifier, you will have to have a container and mix the salt into the water until it dissolves. Then soak whatever item you wish to cleanse. Dispose of the water outside or a natural place, as its not recommended to dump it down the drain in a house.

Smoke/Fire Method
Again, porous items may smell after this one and items with wood should be avoided for this process. For this method, you take the item and pass it through the smoke of the fire. If you use candles, you can also pass it through the flames if it feels right to do so. Campfires and other larger fires can be use, but use caution.

Air/Wind Method
Put your item outside and let the air run through it. When its windier out, it can be more helpful in terms of cleansing. Be careful of what is in the air though, as some people have found more toxic or polluted air much less effective and even damaging for cleansing. With that, air mixed with other elements, e.g. mist, smoke, or even dust, may prove to be less or more effective.

Crystal Method
You can use charged crystals in a grid or around an item for them to soak up the energy from it. After this however you may have to cleanse the crystals or recharge them, so this method may mean extra steps for you.

Earth Method
For this, you bury your tool into the ground for however long is needed. You can put dirt into a pot or another container then bury the item in there, but it is recommended to put the dirt outside afterwards and to not reuse it. You can also use sand for this method.

Sun/Moon Method
Celestial bodies are quite effective for cleansing. Simply let your item sit in the sunlight or moonlight for however long is necessary. For the moon, it is recommended it has some light or be in the full moon phase rather than putting something out under the dark moon, unless of course it works with your path more. Stars may also work for you, in which case the dark moon would be the optimal time to cleanse the item with starlight.