a little practice and the dents are minimal...they don't hurt the ammo except for appearance.

I load 50 cases in a loading block and spray about 1-2 seconds from each of four directions and at an angle that allows some spray to get inside the necks about 1/2-1/3 the way down.

Allow the spray time to dry and have at it.

After resizing the spray can be remover with a vibro bowl or a solvent....if you use a solvent I recommend a air compressor to thoroughly dry each case.