pipe cleaner

Either be SUPER careful or I use a small silicone piece, like the stuff we use to hold our bbearing wheels on
 
Try nipping the end until you get a relatively "smooth" end and then carefully insert into the wheel bore.

+1 to the silicone piece, I'll have to give that a try Chief.
 
Use fingernail clippers to cut it, that will give you a much cleaner cut that needle nose pliers or side cutters
 
An electronics supply store will sell you 1/16" shrink tube. Clip 1/2" of fuzz off pipe cleaner end down to the wire center and slip a 1" piece of shrink tube about 1/2 way onto pipe cleaner wire end. Heat the shrink tube a bit with match or heat gun and watch it shrink down to small enough size to cling to pipe cleaner wire and protect the wheel bore when inserting the pipe cleaner.
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