Yes, it is cotton and will burn if dry, so no dry burning with those wicks in place. It's candlewick so, no guarantee it's even clean, much less sterile so, boil it for 30 mins, or better if you have a pressure caner, put it in there and bring it up to pressure for 15 minutes, then cool and let the pressure drop before opening the caner.
Don't make the cotton wicks any longer than the original silica wicks were and make the diameter just do it fills the space but isn't compressed or overly snug in there - cotton swells when it gets wet, and it will be getting wet, too large a wick and you get dry hits, too small and it will leak or gurgle.