I thought I was the only one that greased the contacts. I have always just used a very light coat of Vaseline and it works quite well. I learned this many years ago from a TV repairman. Light years ago, TV tuners were rotary from channel 2 thru 13 and after some time they got dirty and the picture flickered and you were constantly spinning the tuner to get a good contact. The repairman took the tuner out and it was covered with many little knobs that made contact with springs and these contacts got dirty. He cleaned the contacts with an old bath towel till they were shiny and also the springs. Then he coated the whole tuner with a good dose of Vaseline. I know that sounds improbable but having been treated with the Vaseline, the tuner never flickered again. I always figured it was an "arcing" problem rather than a "dirt" problem though.

I know it works because I routinely put a very light film on both ends of batteries before I install them and never have a problem.