Having your troughs clear is important to get you through the winter months. Leaf and silt can block the flow of water and cause ice back-ups. If you neglected to clean it before the weather got cold you can tap it out with a rubber mallet of the butt end of a wooden handle. This will lift the ice out without damaging the aluminum trough. Here are some other ideas that might be helpful too.
Source: https://www.angieslist.com/articles/how-can-i-thaw-frozen-gutter-or-downspout.htm