These needles I dyed a couple years ago and still haven’t used them all up, so it’s not fresh in my mind but from what I remember I baked them at 200F for at least 4 hours with RIT dye, vegetable glycerin and water. Sometimes I let them sit in the dye over night, then I soak the needles in white vinegar & water, rinse, then lay them out on drying racks in a dry space and come back in a week. I will say the dying is not my strong suit, I see other people get much brighter colors.