When your Perfection heater has burned the wick down to where it can't "cam" the Flame Spreader to full height any more, it is time for a replacement wick. Here is the difference between a new Hattersley wick and a used up one.
  You have two choices. Toss the wick and install a new one or replace the cotton wick with a new universal wick from Miles Stair. I have found the universal wicks to be cheaper and you get 2X life over a pre-made wick. Here is the universal wick installed in my carrier of choice, a vintage Perfection carrier.
  The wick is inserted so 1-5/8" of the wick is above the carrier. Use Dental Floss to "sew" the wick to the carrier. Note the use of a vintage carrier provides you with many places to sew.
  Vintage carriers are almost always included in the heater and Fount you just purchased, complete with a suspect wick that you were going to throw away anyway!
Insert the new wick over the inner air tube of the Fount and slide it down.
 
Engage the twin sprockets with the slots in the carrier. Again, the vintage carrier is easier than a reproduction.
  And position the tails of the wick away from the adjuster shaft and into the bottom of the Fount.
Slide the outer gallery over the wick and screw down.
  Pour some water clear Kerosene on top of the wick and install the Flame Spreader and crank the wick up to maximum.
  Light it up and burn off most of the fuzzys.
  After the flame goes out, clean the top of the wick and fill the Fount with water clear Kerosene and burn the wick for a couple of hours to "break it in" By then you should have a fairly good edge and it will provide dozens of hours of service.
 
When the wick does burn down to the un-useable level again, just cut the Dental Floss and raise the wick to 1-5/8" above the top of the carrier and re-sew. You now have essentially a "free" wick because the tails of the wick are long enough to still reach the Kerosene in the Fount with a fuel gauge reading of "0".
Mark the wick carrier so you will know you are on your 2nd raising and the wick will need to be replaced next time.