I have a pile of gift cards that have such small balances that they might be better used in some other (clever) and useful way?
What is the best way you can think of?
You could find a friend who plays a stringed instrument (or perhaps a school band class) and ask them if they'd be interested in taking some or all of your cards. Amazon (and probably other places) sells something called a "pick punch" and those old gift cards are perfect for making guitar/mandolin/banjo picks (a pick is also called a plectrum, but most people call it a pick.) I would have loved to have had one of those gadgets when my boys were in middle school band.. they were constantly losing picks.
use them as handy ice scrapers for your windscreen ?