Ditto the WD-40 approach. I am all for trying the cheapest/easiest/no harm done route before getting into more complicated manners. Despite the repair advantages of having downtube mounted shifters versus brifters, I love my 105 set. I do not want to take my hands off the hoods when I'm in a comfortable semi-tuck.

Only problem with mine, the front derailleur shifts like a pig from the granny cog onto the middle one. Must have the LBS check that out.