Jojoba oil safely be left in your hair overnight and in fact it's called the leave in treatment.
Before going to bed massage some warm Jojoba oil into your hair and then put a shower cap on to prevent the oil from getting onto your pillows etc.
Then in the morning wash the Jojoba oil out of your hair.
You can also mix Jojoba oil with lavender oil and then rub the mixture all over and into your scalp and then let it sit for half hour and then wash it out of your hair.