While not really classified as spells there are certain things you can do to cleanse and consecrate an item.
The day after the Full Moon, take your item and wrap it in a black cloth. Bury the item for approximately two weeks, digging it up again on the day after the New Moon, when the first sliver of moon appears. The earth and the cloth will have absorbed the past associations with the item, positive and negative, and it should feel entirely neutral. Feel free to dispose of the cloth any way you see fit, though burning it would be most appropriate. It would also be appropriate to leave an offering of something sweet (honey works very well) for the earth spirits near where you've buried the item.
You can now leave the item where it can absorb some solar and lunar rays, sprinkle it with pure water and pass it through incense or belfire smoke.
If the item is to be used by only you, you can hallow it to your purpose by breathing on it three times and wetting your finger with your saliva and tracing three X's on the item. You can also say something like;
"Be consecrate and imbued with the hallowing might of the Old Ones (or insert whatever names you feel comfortable with) and increase thy spirit with the power of Sun and Moon and Stars, Sky and Earth, Water and Fire."