I have been using Pure Lemon Oil for a long time. I buy it off the internet at what ever the lowest price is at the time I need more. The last bottle I bought is by Boyajian and I believe I paid $11 for a five ounce bottle and shipping was about $3.00. The bottle I bought three years ago was about $6. This is 100% lemon oil used in cooking. However, I do not keep it in the fridge and it does not spoil or go rancid. As far as logic goes, 100% lemon oil is about as pure of lemon oil as one can get? A rose by any other name, perhaps? As for using other things to treat my fretboards twice a year, I like the results I get from lemon oil, so to each their own.