Oftentimes, after you wear a shirt or sweater a couple of times, it begins to "pill" or get annoying fuzzies on it.
Lifehacker offers this trick that just uses a disposable razor:
To clean pilling off your clothes just spread the fabric across a flat surface (something firm like a table is best) pull the fabric taut and carefully shave the pilling away from the fabric. Be careful with the razor, especially around seams, buttons and stitching because you can easily cut the fabric.
This simple solution works - I tried it out personally! It made some of my t-shirts look like new, in seconds.