cometboy, very good question, and one I haven't seen discussed anywhere. I would like to believe that the J1772 contact design is such that it has a self-cleaning action. For myself, I keep the contact ends of both the car and the EVSEs covered and dry and won't do anything until I start getting intermittent connections. An occasional visual inspection of the contacts is part of my routine maintenance - so far, they're squeaky clean.
If you feel you must do something because you are experiencing a problem, I'd be more inclined to look for a product specifically designed for connectors and with some lubricating (and conducting) properties as well. Unfortunately, the downside of lubricants is that they also tend to attract dirt. Without any personal endorsement, I've heard of good results with Electrolube products (http://www.electrolube.com
) - but their large selection (of cleaning and lubricating products) means you need to do some homework for this application.
Maybe a good question to pose to the manufacturers of J1772 connectors?