Yes, it really is best to double glass that sort of candle. I saw a candle in my OB-GYN clinic once and it was full of something like baby's breath or some such thing, it was hard to tell, but I know it was flammable whatever it was. No double glassing, nothing between the flame and the flammable stuff. I thought "oh gosh, I hope the clinic is here the next I need to come"