Side mirror shake

[JML07denali]

My drivers side mirror shakes just a bit on the highway and it drivers me crazy. Is there a way to tighten it? Hate to have to buy a whole new mirror.

 

[ccapehartusarmyINF.(ret)]

when the stupid defoster deal in mine went out and dulled up my mirror i got a new one at a upull place for like 50 bucks

 

[JML07denali]

Thanks