To give hair back its sheen, post-holiday, warm up a couple of dessertspoonfuls of macadamia nut oil and massage gently into scalp. Comb through to the ends of hair, and allow it to sit for up to two hours before washing your hair as usual. Massage any extra warm oil into cuticles or rough heels and elbows. (Usual nut allergy warnings apply, of course, if you have a problem with nuts.)