Essential Oils and Wax

I'm  making little spa boxes for my family and friends for Yule/Christmas, and I am going to include some tealights in them. Now, here is my question: Is it possible to melt the wax using a candle warmer, put in some essential oils, and then let it re harden? Can you even use essential oils in wax? I just remember that my previous adventures in candle making included fragrance oils, not ...