Here are some tips to keep your candle burning clean and almost soot-free! Why almost? Because soot has and will always exist. In fact, soot particles are what make a flame burn yellow.
1) Trim wick to 1/4 inch prior to lighting
2) Burn no longer than 4 hours at a time. Save some of those forest scents for another session :)
3) Time for a new candle when 1/4" of wax is left.