Here's a tutorial courtesy Lunamoth on restoring factory curl. I don't know if this method will work on all ponies.
This Re-Curling tutorial by Whippetluv is one of the best I have ever found:
Step 1... Frizzy haired pony
Do step 3 and 4 several times.
Heavily applying conditioner and running a thin comb through the hair will straighten most minor frizz. My secret weapon is Pantene. I've removed frizz using this that other shampoos and conditioners didn't even touch. Fruity or floral scented shampoos and conditioners are also popular with collectors.
Most common in beddy-bye-eye babies and newborn twins, pony mohawks can be persistent and annoying. To tame pony mohawks, wet the ponies hair, pull it down around the neck, making certain it is smooth. Fold a piece of paper towel over a few times and wrap it tightly around the neck/hair. Secure it with tape. Let the pony sit until the hair is dry, then remove the paper towel.
You want this type of hair to be poofy, so comb or brush it with whatever you have that makes it puffy, but be careful not to pull the hair out (regular plastic combs are probably your gentlest option). You'll likely lose some of it, which is ok. If it's only a little you won't be able to tell. You can wash and condition their hair with the same shampoos and conditioners you use on your other ponies. Their hair is supposed to be soft, so use tons of conditioner and leave it in for longer periods of time if needed. I've gotten reports that carpet cleaner like Resolve Triple Oxi will help whiten dingy, grayed perfume puff hair.
Photos courtesy BabyIceCrystal.
When a pony's original hair is just too far gone, replacing their manes and tails can make a huge difference. AeraCura and The My Little Pony Hair Color Matching Guide also have provided really nice hair color guides. For G2's see The Lavender Lagoon Rehairing and the Colour Matching guide.
Barbie Designable Hair Printable Hair Extensions could potentially be used for re-hairing ponies with horizontal stripes in their hair (these guys). Who knows how long this will be available for sale. Here's a review about it, and here's a discussion about it.
Ever wonder what other collectors think of re-hairs? Here's a cute poll: The value of rehairs: questions/concerns/opinions?
Photos courtesy Mandy85.
This is a compilation of information from this thread at the MLP Arena: Re Pinking.
Using either powdered or liquid Rit Dye, mix it in a bowl or sink of water. Read the directions on the packaging to decide what proportion of dye per water to use. The more dye you put in, the brighter the pony's hair will turn out, so go easy, you can always add more. For non so soft ponies, comb the dye through the hair, then rinse with hot water. Repeat as necessary until the hair is the shade of pink you want.
You have to be careful not to get the dye on so soft ponies' flocking. You can hold the pony upside down while coming in the dye and rinsing. If you're careful, gravity should keep the dye away from the flocking.
Some collectors prefer to simply dunk the ponies mane and tail in the dye bath, instead of combing it through. The powdered dye reportedly won't stain all bodies, tinsel, and when used in a multi colored mane or tail. Remember, unlike dyeing a body, you won't be leaving the hair in the water for more than a few seconds. It can dye their bodies if you leave the vinyl in contact with the dye for too long.
More interesting research by BlackCurtains! Light Experiment - Fading Pink *Updated - Week 6* Basically, what she found was that pink hair only took six weeks to completely fade to white when exposed to sunlight, but was not affected by artificial light.
Whitening toothpaste (paste, not gel), Dawn Dish Detergent, OxiClean, CLR, and Rit Rust Remover can all be used to remove tail rust. The power of cleaning chemical you choose will depend on the severity of the rust stain. Any chemical treatment to a pony's hair usually leaves the hair needing a wash with Dawn dish detergent and a conditioning treatment. Be extra careful to thouroughly rinse all chemicals off the pony's body and wash with Dawn as needed. It's best to try the whitening toothpaste first, as it is often all that is needed and will allow you to avoid harsher chemicals.
Photos courtesy BabyIceCrystal.
The hardest part of replacing tinsel is finding tinsel that is fine enough and the right color. Fabric and craft stores often carry it for sewing. I read somewhere that the tinsel used for making fly fishing lures is often a good match. Once you've picked a color, you can replace the tinsel using the same techniques as doing a re-hair. If the holes are clogged with glue and hair, you might have to remove some glue to do this. You can secure the tinsel with the same glue you use to secure a re-hair. Here are some places where you can buy tinsel:
For any color of tinsel, here's a tutorial and photos courtesy StrawberryReef. *disclaimer* StrawberryReef has reported some difficulty getting consistent results with this method, so please use with caution.
1. Wash hair with shampoo and rinse in warm/hot water.
2. Apply conditioner and comb through hair. Do not rinse.
3. Apply fabric softener to hair and comb through… hair should feel pretty slimy.
For more problematic frizz, back to Whippetluvs tutorial:
Step 1... Frizzy haired pony
Do step 3 and 4 several times
If you want truly straight hair you are now done. Just stand pony up and comb hair how you want it to stay forever."
A tip I haven't tried yet but sounds worth putting out there is to soak frizzy hair in coconut oil for several hours before washing and styling. I'm definitely going to be trying this one!
Photos courtesy Truevampiress.
Here are some popular places to order replacement hair:
Need some help with general styling of your ponies' hair? Here are a couple of tutorials to get you started!
Photos courtesy Cyberunicorn.
Search for "Finishing Tinsel" on Ebay.
Elish2 made a youtube video about styling Perfume Puff hair: Brushing and Styling a MLP Perfume Puff
If you're trying to dye faded Perfume Puff hair and the dye won't take, some solutions may be, a vinegar treatment, salt, or a dye fixative. Courtesy Hathorcat See the "Re-Pinking" section for info on how to dye pony hair.
To re-hair a perfume puff collectors often use yarn or mohair: Rerooting Tutorial - How to reroot a doll with Yarn
4. Rinse hair with WARM/HOT water...it's ok to leave some conditioner residue.
5. Separate tinsel from hair (I got impatient and did it without separating and it still worked, but I would think the results would be even better if you are able to just attack the tinsel. I had to go over the tinsel more when it was mixed with the hair) 6. By this time the hair should be just damp, not soaking wet.
7. Separate hair into small sections. While separating, pull any short/broken pieces of tinsel out with the tweezers (pulling close to the base of the hair).
8. Wet the dryer sheet and pull sections of tinsel/hair through the dryer sheet. You will go over the section of hair approximately 10 times with the dryer sheet until the hair/tinsel is a bit tacky/slimy and should feel like it is covered with conditioner.
9. The tinsel should stretch out straight but you will still feel crinkles when you run your fingers across the section.
10. Run the section of hair through a curling iron set to LOW (I was able to do it on HIGH as well, but I never let the curling iron sit on a section for even a second, the iron was always moving over the hair.). Keep running over the section until you no longer feel the crinkles. (The pic below shows the small tinsel section on the left has already been run through the iron.)
11. The section will become stiff and flat. Trim any tinsel that is longer than the hair with scissors.
12. Once you have gone over all the hair, rinse hair completely with COLD water and let dry. (My AFTER pictures were taken at this stage.)
13. I thought her hair still felt a little gummy so I re-shampood her and tinsel remained straight. Make sure and use COLD water."
Einhornbaby at the MLP Arena provides some instructions for re-hairing Petite Ponies: "Soften the glue with hot water, pull out the tail (careful, you dont want to pull the tailbow too!!) and make a new one where you cap the end that will go into the pony with some sticky tape. Then put some glue into the hole in the tailbow and carefully put it in. Its a pretty sensitive task since petites are small, but if you take your time it will look very nice afterwards."
You can use any shampoo and conditioner to wash and condition your pony's hair. Everyone seems to have their favorite. Fabric Softener is also a favorite method for conditioning pony hair. Some people even wipe wet pony hair with fabric softener sheets.Some ponies have gotten some really strange stuff in their hair over time. For more stubborn gunk, try washing the hair with Dawn dish soap or an OxiClean bath.