You could heat some pure camphor in cocinut oil and massage your scalp with it and leave it overnight. Wash as usual the next day. You could try mint essential oil too.
how do I get rid of a flakey dry scalp with dandruft
Oh and Onion juice ofcourse. Grate it and press it with a spoon on a sieve. Collect the juice and apply all over the scakp. Leave it for 2 hours with a shower cap or plastic baggie on and wash. Works wonders! Plain yogurt is also great for dandruff :)