Hello there, I've been a doll artist since 1998, and a wig stylist since 1994. Over the years I've come up with many tips and tricks for restoring and repairing synthetic hair. I love to use KatSilk Saran hair from RestoreDoll.com because of the great selection, but the problem is, the hair has a "greasy" feeling to it, much the way the Monster High dolls get. So here is my personal step by step process:
1. Put your doll's head in a mug or cup and fill with rubbing alcohol (enough to cover her hair) and let it soak for 5 to 6 minutes. You don't want to soak it too long because it will begin to get in the head and dissolve more of the glue inside. Do not use acetone! The scalps of all the dolls are painted with the same paint as the face.
(In the most extreme of cases, after soaking, rinse with water, then take some Q-tips dipped in alcohol, and rub the scalp in between the hair plugs. Use your fingers to separate the hair into natural parts where the hair is rooted, this is easiest while the hair is wet. Again, this is optional)
2. Next, rinse your doll's head, in the sink, thoroughly with luke warm water. Make sure to squeeze the head slightly to really clean down to the root of the hair plugs.
3. Next, apply dish washing liquid soap to the scalp and hair (I like the pump foaming kind). Make sure it says on the label that it has a de-greaser component of some kind, or says "tough on grease". Then work the soap into the doll's scalp and hair as you would shampoo your own hair for about 3 to 4 minutes. Again, rinse clean with luke warm water.
4. Use a clean towel, or white paper towel to squeeze out the excess water and sit your doll aside to dry. If you are in a hurry, use a hair dryer on cool setting to speed up drying (do not use heat! it will melt your hair!).
5. When your hair is completely dry, brush it out. If your hair begins to get "fly-away" or have static, don't panic! This is actually a good thing because it means the grease is gone! Simply take a clean laundry dryer sheet, wrap it around sections of the hair, starting at the scalp and working to the end of the hair. Do each section twice. Then brush the hair again, if you still have some static fly-a-ways, simply repeat the dryer sheet step, it will take care of it.
Now your hair should be silky and smooth, and free from grease. After you have completed these steps, and still find it seems a bit greasy, go back to step 3 (dish washing soap) and let it sit a bit longer before rinsing. Another tip to try after completing the steps it to take a powder puff with a tiny bit of corn starch on it and pat it evenly all over the doll's hair from root to tip; not too much! Then use a brush and brush it in thoroughly to help remove excess and work it into the doll's hair. If there is any grease, it will instantly absorb the corn starch. Again, I recommend this technique only after completing the steps listed above. Putting corn starch on an untreated greasy doll will only make a clumpy mess. Remember, at the end of the day, this is synthetic hair, not even high quality synthetic like wigs are made with, so using human shampoos and conditioners won't help.
These steps will most likely straighten out any wavy or curled hair (if you are concerned with this, use cold water rinse to help save any curls). However, after your hair has been de-greased, you can always set your hair with bobby pins or small rods and use a boil perm or steam perm technique to add back waves or curls. Of course, that's a whole other subject! GOOD LUCK!
During transportation or warehouse storage, dolls can get hot enough to melt the glue in their heads, causing it to seep out of their root holes and make that icky, greasy hair we all hate. We can also accidentally cause this by pouring boiling water over the hair to style it, so use caution.
For my two cents, I've found adhesive remover does the job, and makes it super soft feeling! No damage whatsoever as far as I can tell (I did this on two of my dolls about a month ago. Still fine)