The material body is an exact replica of the etheric double through which it is built and maintained.  As your body has limbs, so does the etheric double, and every time you move your material body the etheric double moves in unison. 

The  etheric double cannot be removed from the material body until the body is no longer needed.  However, it is possible to train yourself to use freely your etheric limbs, by lifting them out of the material form.  An etheric limb has few of the limitations of the heavy material body.  It may, for example, be used to penetrate and extend into gross matter.       

For properly enacting certain exercises, and as an indispensable tool for healing, the development of etheric arms and hands is vital.  When first freeing your etheric hands you’ll visualize an elemental of a hand and arm that rises out of your material form.  After a while you will begin to feel some heat in your material arm as your etheric double begins to replace the elemental. 

With steady practice, preferably daily, you will develop greater control over your etheric limbs.  In time you may find yourself using your etheric hands in healing, e.g. to adjust bones in a mis-aligned back or to lengthen legs.       

The psychical and noetical bodies have their own etheric doubles and as you advance in your self-conscious awareness you will find that you can train yourself to use these hands for much greater work!