what I do is dig up an area about 6'x6' and put down a 40lb bag of mineral salt and a 40lb bag of stock salt. Then I mix it up with the dirt really well. I also try to refresh it before a small shower is about to come. That way it mixes with the dirt well. The blocks work well, but I found if you already have an established mineral lick area (like what I discribed above) they work especially well if you place it when the lick area needs refreshing. I also have learned DO NOT change mineral locations. Once you have an area established, keep it and keep it going by refreshing it. I think they say you only need one mineral lick per 100 acres. Of course if your deer population is heavy you can adjust this.
...and on that day when my strength is failing, the end draws near and my times has come, still my soul will sing Your praise unending, ten thousand years and then forevermore!