In addition to the air dryer I also install dessicant plugs in all 8 spark plug holes. They generally last about 6 weeks to two months before turning pink. At that point I remove them and put the dessicant in the oven at 250 degress until it turns blue again. Before putting them back in I also spray the preservative oil recommended by Continental into all the upper spark plug holes, in through the opening where the breather tube goes and into the oil sump. This spray unit which I got at Aircraft Spruce works perfect for that. It delivers a nice fine mist of the preservative oil.
