CF card emory

I have several Extreme III cards, 16GB and 4GB.  I notice lately that my cards are full in my Nikon D3 but really they are only holding a fraction what they used to hold.  Example my 16GB card only fills to about 4GB.  I always reformat in the camera before use, is there a way to recondition and reclaim the memory space?

For better exporsure and greater chance of gettinng a useful response, you should probably post your question in the appropriate board:

This board is for the SanDisk Memory Zone app. :wink: