As mentioned it's mostly for aesthetic, but for me it's important to cover up what I did to all my external screws to prevent the rusting out mentioned by others. I went and 'entombed" all the exterior screws in "Eternabond". I used the double sided tape and simply cut two small squares leaving the top paper layer on the top square so it wouldn't stick to the vinyl protective molding. I removed each screw, put one square over the hole, wrapped a little Eternabond around the screw threads, reinstalled the screw and then put another square over the top that way the entire screw including the threads are covered in Eternabond. I don't trust caulking to really seal those screw heads up and much prefer the better adhesion of the Eternabond microsealant. Here is a pic of what "My treatment" looks like ....
Step 1:
Step 2:
![](http://i1325.photobucket.com/albums/u639/12491/Eternabond%20install/TrimHole3_zps8b9d9fdc.jpg)
I fully appreciate the hidden damage until it's too late that ALL SCREWS will suffer from "wicking" given enough time. It might be two years or twenty, but eventually there is a high probability that they will start "wicking"
Larry