I am not sure the ink will come off if you boil the pony, however it is good for cleaning dingy ponies, and getting rid of pin dot mold. If you boil ponies i think it dries out the hair. There is tutorial button on the top that should help you out.
With the hair, there are many methods to getting ride of frizz.
some soak the hair in fabric softener, others use a good conditioner and leave it on for a day or two.
However my method is the wet hair with a deep conditioner and a straight iron. here is the steps.
Okay i guess i should have taken before and after pics, If a pony has brittle dry hair or its really tangled, i only use this if it is really bad, like after i have tried with out success.
example i had a firefly come to me with very badly damaged hair i have no clue what happend to her i couldn't even get a comb through her hair, after treatment it still wasn't perfect but i can now comb it without tangles.
get a really good deep hair conditioner i use (smooth'n shine therapy silk fusion) bought at dollar store also can be called critical hair repair for dry and damaged hair
directions
1) try to wash the ponies hair first
2) then slather on the conditioner really thick wait like 5 min
3) comb through what you can, but don't worry if you can comb to much
4)
leave conditioner on while doing this step, start at the base of the tail or mane use straight iron (i set mine to the middle setting)
5) comb hair again, i usually work the hair from the bottom up,
make sure the ponies hair says wet
6) add conditioner as you go, continue until you can freely comb through the hair.
7) rinse and style as you would normally, hair should be smooth and soft.
caution should be noted, I do this at the bathroom sink be careful, when using straight iron around water, also try not to burn yourself.
good luck with the damaged pony hair. have fun
This thread may help you too.
http://www.mlptp.net/forums/mlp-discussion/59417-how-do-you-clean-your-ponies-2.html