For many dolls, their hair is their crowning glory, showing off both beauty and realism in the doll's build. That is, unless the hair is a tangled disaster, in which case it's more of an embarrassment. The best way to de-tangle your doll's hair is to use liquid fabric softener or children's conditioner, and this should be part of your regular maintenance routine.
Pre-Treatment: Wash the Hair
Doll hair is easier to untangle when it's clean, so the first thing you should do is wash it. Soak the hair in a solution of warm water and mild soap or children's shampoo; if the hair is greasy, use hot water instead. Gently scrub the hair, taking care to not mash the tangles together -- while the de-tangling solutions can still fix them, there's no point in making the job any harder on yourself. Rinse the hair with warm, clean water when you've finished scrubbing.
If your doll has wavy or curly hair, use cold water instead. Hot water will straighten the hair, which is almost as undesirable as the tangled mess.
Option One: Liquid Fabric Softener
Liquid fabric softener is a popular option for removing tangles from doll hair. There are two ways you can do this: soaking and spritzing. For the soak method, dilute the fabric softener with one part water to every part fabric softener. For the spritzing method, put a tablespoon or two of softener into a spray bottle and fill the rest with water.
For the soaking method, put the solution into a cup or bowl and soak the hair in the solution for about 20 minutes or until it's thoroughly saturated. After soaking, run a small wide-toothed plastic brush through the hair and work out the tangles, starting at the ends and working your way down to the roots. Hold the doll's head tight to prevent damage to the hair or the doll itself. Rinse the hair of any remaining solution with warm water, or cold for curly-haired dolls.
For the spritzing method, put the solution into a clean, empty spray bottle and spray liberally onto the hair. Work the solution through gently with a small wide-toothed plastic brush and work out the tangles in the same end-to-root manner as described above. Reapply the solution as necessary during the course of de-tangling. Once the tangles are worked out, rinse the hair with cold or warm water.
Option Two: Children's Hair Conditioner
A less popular option is children's hair conditioner, which is mild enough to not damage the hair, while also helping to loosen the tangles. Gently apply the conditioner to the hair and work it in thoroughly, then rinse. Using the same end-to-root technique described above, gently brush the hair and work out the tangles.
Finish Up: Drying the Hair
Once you've finished washing and de-tangling the hair, you just need to dry it. Press the hair between two layers of a towel, making sure the hair is stretched out and straight. Don't apply too much pressure, just enough to absorb the water. If you're worried about the hair losing its curls or waves, you can let the doll air dry.