A great tip for reducing oil in your hair.
Apply the clay mask (multani mitti) on the scalp and hair strands section by section. Let it stay for and hour or till it dries up completely and then wash off. You do not need to shampoo. Its up to you.
The clay mask has the same effects on hair as it has on skin: it soaks in the oil, keeps the hair moisturized and soft. Another advantage is that it straightens your hair naturally.