apols if repeating but havnt read thread.
have just the other day gotten rid of all cradle cap on my 3 and 4yos in one fell swoop after all this time. was a piece of piss too.
got baby oil (or olive oil will do it. in fact any oil will do it, but you dont want them smelling like a chip pan )
liberally applied oil to head, working into hair down to scalp, covering all affected area.
got one of those nitty gritty nit combs, with the twisty bits.
used the comb to v gently comb out all the oil, holding it nearly flat to the head.
had a towel handy to wipe off the comb after each sweep.
all the crap came out with the oil. shampood afterwards in the bath.
did it in front of the telly so they were sitting still/distracted.