There are several ways to neutralise an object that has had a curse placed on it. If the curse is weak, a simple purification may be sufficient: immerse the object in a pile of salt or salt-water, expose it to the smoke of incense, or spray it with holy water, the curse will be removed and the object will be purified again.
If the spell is stronger, you may need to find out how this curse works and prepare a counter-spell if necessary, with ritual and incantations designed specifically to remove the effects of the curse.
If you are looking for a temporary solution to remove a curse, you can put any copper object on the item (for example, an ordinary coin will do). Since copper has the ability to drive negative forces away by deflecting them and returning them to a state of balance, it will absorb and dissipate the energy released by the curse, preventing its effects (although perhaps not always completely). However, due to saturation of energy over time, this way is temporary. Although to make the curse-removal more effective, you can also sprinkle salt onto both the coin and the cursed object.
I also need to note that sometimes, what may seem cursed is actually haunted. If there is an evil spirit clinging to the object, you can remove the curse in a manner of ways: either through an exorcism, by banishing the evil spirit, or by destroying the object.
Successfully performing a spell is an art that comes about with practice. The better you are at working with magickal energy, the better your results will be. The Essence of Magick is a guide which teaches you how to cast spells that work.