Over the years I have tried every type of rock, block, lick, jam etc. and the best thing I have found is the 50lb. generic blocks that you can buy at TSC for $6.00 and the lose salt/mineral 50 lb bags that you can get for $6.49 per 50lb bag at TSC.
The deer in my area will continue to hit them until about Sept 21st. After Sept.
21st. apples seem to work the best for me and then corn and Buck Brand as the temps continue to drop. Pike
Below is link to my photo album that has pics of over 70 + different bucks hitting my blocks and licks this summer. Pike
http://smg.photobucket.com/albums/v294/jeffpike/2009%20Trail%20Cam%20Pics/