I'd like to share my experiences from years and years of setting up our artificial Christmas tree and dealing with those annoying lights.
As I get the site up and running, I know it's late but I was trying to fix Christmas lights (go figure), I will keep updating the content.
Right now, the best tool I can recommend is the Light Keeper Pro:
Does this look familiar? An entire set of Christmas lights that are black because they are burned out?
Didn't think that those "mini" Christmas lights get hot enough to melt plastic - WRONG!