I had this same problem but did not want to mess around with my airbag (and did not have the money to pay someone to do it!) so I sprayed the turn signal stalk with electrical contact cleaner. I figured this would be better than WD-40 because it is what you would use to clean the connections anyway, it evaporates quickly, wont harm other plastics or connections and WD-40 can aid in attracting dirt and dust and this gumming up is the problem we are trying to fight (like why you use graphite in locks and not liquid lubricant. I sprayed a bunch where the stalk meets the column and made sure to do this with the stalk in all the positions it can be in (i.e. left and right turn, highbeams and highbeam flash). I let the contact cleaner evaporate for 15 or 20 minutes before switching on the ignition to avoid smoldering/setting it on fire. It has been a week or so and the problem seems to have gone away, and if it comes back I will try to "clean" it again in this manner. Thanks for all the advice!