Yoga is a fantastic way to open your body and, as a result, to open and balance your chakras. The camel pole, for example, can balance the heart chakra and throat at the same time. A regular yoga practice can work wonders for restoring balance to the mind, body and soul. TaiChi and QiGong are equally beneficial practices that open your chakras and balance your energy.
One way you can unlock or rebalance your chakras is by doing certain yoga postures. Specific breathing exercises and meditation practices can also help. Certain healers can affect the physical counterparts of the chakras with external aids or with psychic energies that can be useful in treating various physical or emotional imbalances, but true awakening of the chakras cannot be achieved by an external person. No external person, machine or object can open your chakras to you at their level of yogic functioning.
The use of certain diets, herbs, or gems can be helpful in paving the way for chakra opening, but these are only external supports. They cannot open the chakras any more than asanas alone can produce meditation. A guru, or someone in whom inner consciousness is awakened, can provide guidance or initiatory experience, but they cannot do the work for us. True opening of the chakras requires the expert practice of yoga, which can take years, sometimes lifetimes, to achieve and which is derived from deeper yogic practices of pranayama, mantra and meditation along with a disciplined lifestyle.