AC Motor Oil Wick Replacement
I havent done one in years , not really hard if the sleeve is not two badly worn, pull the bolts that hold the end bells and slip the end that is falling apart off, examine the sleeve if it is worn you will need to get a shaft measurement and the outside diameter and replace it the ones I remember doing had wool packing but you said this was cotton, .there are 2 types some have an end plate (the easy ones) pull the plate fill with material and put the plate back on, saturate with oil and reassemble the end bell on the shaft and tighten the bolts, the tough  type ,. same start remove the end bell
 Carefully press out the end cap seal so you can re use it
once that is out you can press the sleeve out to the center, use caution this is very poris and may be brittle if it overheated, if in good shape repack the "void" and as you get close to full slip the sleeve back in 50% then continue packing untill no more will fit, it helps to oil the material prior to pressing the sleeve all the way back in because once it is damp it stays in place better once you have the sleve back in replace the end cap seal, saturate with oil , replace end bell and bolts and you should be good to go