you should be in a dark room as its nature is to create melatonin(in a dark environment)
I'd use the 3rd eye mudra as its directly correlated to the 6th chakra and pineal gland, vibrate into your pineal gland/6th chakra every night for 40 days while affirming something like "my pineal gland is completely open and cleansed in a positive and healthy way for me"
you may also need to do a cleansing spell before so keep that in mind, but atleast clean it twice a day(along with your other chakras) via regular meditation.
remember to keep working on the other chakras during this as to not build imbalances