Anything and everything you put on your altar or plan to use in a magickal way, should be cleans, blessed and charged. If you don't have a specific reason to charge it, then cleans and bless it. You don't want someone else's negative energy rubbing off on you or your family.
Physically wash the item ahead of time. Clean it well, sprinkle or dunk in salt water then rinse off and dry. Visualize all the negative energy coming out of the item and going down the sink in the dirty water. Run clean water down the sink to make sure all the dirty water is out of your house. Mother Earth will take care of the negative energy. Burying it ahead of time works even better.
This is to be done in the Purpose section of a ritual preferably during a full moon.
In the center of your altar should be a pentacle. Place what you are going to cleans, bless and charge on the pentacle as much as you can. If you have a lot of items or really big items, then just make sure they touch the pentacle. The pentacle provides protection for whatever it touches and where it is at.
If the item is something that you can pick up, I'll pick it up and hold it over the incense's smoke. As I trace a pentacle with the item over the smoke I say, "Fire and Air, cleans and bless this (name the item)" Then I hold it over my cup of salt water which has already been blessed and say, "Earth and Water, cleans and bless this _______". I then touch the water with what I am blessing or put a drop of the water on the item. Then I take the item and place it in front of my Celtic Cross or whatever you use to represent the Divine and trace an invoking pentagram or whatever symbol represents the Divine to you and ask the Divine to cleans, and bless and charge this item. Name the purpose you have planned for the item or just say, "May it serve me and I serve thee." Visualize a white light coming from the item that represents the Deity and flooding into the item you are charging. When it feels fully charged, set it down off the pentacle and go to the next item.
Make sure everything touches the pentacle before you cleans, bless and charge it. Once a year, after my dedication anniversary I do this to all of my altar tools, divination tools and my stones. If I buy anything that goes on my altar or will use in my circle I do this. You never know where it was or who handled it before you got it.
For my computer, and other large items I can't move, I take the ritual to them. I would use the same words, just take the incense stick trace the pentacle over or in front of the item you are blessing. Dip your finger into the salt water (Holy Water, Brine, witches water, etc. ) and trace the invoking pentagram on or in front of the item you are blessing. For the charging, I use myself. We are in the image of the Divine. So call upon the power of Mother Earth through your feet, the power of God the Father through your crown chakra. When you feel yourself filled with the power of the Divine, hold it till you are ready to bust and then from your hand, push the Divine energy it into the item you are charging. Using yourself as a conduit for the Divine you are cleansing, blessings and charging all at once. I've done this for my house and land. Don't forget to ground yourself by eating of touching the ground.
Usually this kind of magick is done during the full moon or just before it, but anytime is good. The Divine is always at full strength. Matching up moon phases and planetary alignments are only helping you stack the deck in your favor. Magick wise, it's better to go with the flow then against it.
Remember! this is only my way and by no means the only way. I hope it gives you ideas on creating your own cleansing, blessing and charging ritual.
Happy witching <];-)
Starlight