Cruising the internet, I've found many good articles containing instrcutions on re-rooting. However, the following article contains very good information on the various styles of re-rooting and includes instructions on re-rooting eyelashes! You may devise your own style of re-rooting, but I've tried all these methods, and they work well.
Removing Old Hair: If you have a doll you'd like to reroot, you'll have to begin with removing the old hair. To do this, remove the head and cut all hair off close to the scalp. With a pair of needle nose pliers, carefully begin pulling the hair plugs out from inside. This can be time consuming, so be patient!
Methods of Rerooting:
Needle/Knot method: Thread a needle with about 20 strands of doll hair. Insert the needle on the outside of the scalp. Pull the needle out of the neck hole and remove the hairplug from the eye of the needle. Tie a knot on the plug and pull the hair plug from the other end until you feel tension. Cut the hairplug at about 1/2".
Punch method: To do
this method - a special tool is needed. You can make a "puncher" by taking
a cheap paint brush and pulling off the brush part - this leaves the handle.
Take a medium size needle and clip open the eye of the needle with steel
wire cutters by clipping the tip of the eye ONLY. Also clip off the tip
of the needle. Take the blunted tip of the needle and glue it into the
handle of the paintbrush.
Where to find hair: Finding hair for rooting may be one of the more difficult parts of rerooting. Many times you can get hair from another doll - also called a donor doll. Some beauty supplies carry hair, and you might also try your local Asian importer. If you ask around you will find what you need. There are also several individuals in the field of customizing who sell hair. Another thing to consider is rooting your doll with a nontraditional form of hair. Many people use thread, yarn, and just about anything you can think of. Let your imagination guide you!
Rooting Patterns: One of the easiest rerooting projects is to reroot into the existing holes. The next easiest project is to reroot only the outside holes along the doll's forehead creating a circle - then pull this into a ponytail. With the pony tail root, the inside of the scalp is purposely left empty because to root this inner circle would create too much volume for the ponytail (this is the rooting pattern for the original vintage ponytails). To learn about more complicated rooting patterns, try observing the rooting patterns on existing dolls.
Rooting a part: Rooting a part can depend on the method you are using for rerooting. 1) One of the easiest ways to do this if you are using the needle/ knot method is this: root one whole side - then when starting the other side - bring your needle down (or up whatever method you prefer) into the first side. 2) When using the push method or anchor thread method - anchor the strand of hair then divide in half - weave one side to the other so that no scalp is being shown in the part.
Take the head off. Use 5 or 6 strands of doll hair and a long needle of medium thickness. Thread the grouped strands of hair through the needle. Starting at either end of the eye and using the black eyeliner as a guide, insert the threaded needle through the outside of the head, and thread through to the neck hole. Remove the needle and tie a knot at the end of the strands. Pull the hair back from the outside. Repeat this process until lashes are as full as desired. Trim to desired length.