I have 3 manual egos and 3 automatic. What is working for me is I always put a newly filled cartomizer on my manuals and then after a bit I will put it on my auto batteries. This seems to help keep juice out of the hole on the auto. When I clean the battery, I take a q tip with rubbing alcohol, roll the q tip on a paper towel so it is not too wet and clean all my threads and inside, then I wipe it all with a paper towel. I do this each time a charge. I am pretty new so don't know how well this will work long term but works well so far.