If they can fit Id dump the Birthday candle and go with Ither a tealight or Shabbat candle (even cut down in lenght). A birthday candle will crumble and turn into a pile of wax crumbs in your kit in no time. With a teacandle you can also teach how to use the metal cup base to make a oil/fat lamp with cotton string. also add cotton string since it can be used for many wicking and water retrieval purposes even with its size. You can lead water that is dripping down a rock side with it into a cup or bottle.