The best salt lick I had on my place was my wife's grandfather's old smoke house. He used to put up salt-cured hams and such and the deer had licked a ring 6" deep all the way around it, and there was a hole 2' deep right in front of the door (I guess more salt was deposited there). It hasn't been used as a smoke house for 25 years, and the deer have finally pretty much stopped using it.
Where I used to live there was an old smoke house. Cattle ate all the ground around the house and licked the cement-block walls clean of paint.
Yep, I have also saw deer tear the ground up right beside the highway, where salt had been piled up in the past for winter use of salting the roads! I have also watched them lick the screw in steps to my stand, and once while fishing for a dropped release, I had 2 different bucks come along and lick/chew my pull up rope that I was holding the other end of at the time! lol All I can figure is they were getting some salt from where my hands/likely sweaty when I installed the steps and handled the rope! I have since started spraying my pull up rope with scent killer!
Although that day it was like bait for these young 2.5 yr old bucks!