I had read some forum postings when I was researching weather cameras about the use of a polarizing filter.  So, I decided to give it a try because some the clouds and sky images from my Woicik Weather Camera looked washed out.  I purchased a cheap 35mm lens polarized filter at Amazon.  With the current mount for my webcam, I was able to put the 35mm lens against the windows glass and it stayed in place.  The results of the before and after are below.

Before polarization filter

After polarization filter