I have used them in soy and they crackle great.  I was very pleased with them and I use them in my candles.  They were just ordered fresh, they are not factory seconds, or found in a warehouse somewhere.  They are the best wood wick I have found.  

If you need help picking out the correct wick size, just message me.  Remember, you must always test burn your candles to be sure you have the correct size.