Next best thing from trophy rock
If anyone has heard of trophy rock or hasnt, its %100 pure mineral rock straight out of the ground and it works extremely good.
Anyway, the next best thing from it is the block topper you can find at wal mart. It comes with a jug of the foaming powder and a jug of molasses and other minerals that you pour onto the powder.
I took 2 4lb blocks of salt and layed them on their side next to each other and dug a hole just barely bigger than the blocks, poured the powder around the blocks and on top of them and around them. Basically covering a 3'x3' area with the powder then pouring the molasses stuff onto the powder. It foamed up a place about 40"x40" and about 4" high. Took awhile for the deer to find it but now theres a hole the size of a beachball where the blocks once were.