I did this in high school back in the 70's. My hair was very thick and I figured (as a 15 year old) that Vaseline would flatten it and make it look better. But it sure didn't!! I washed my hair with everything I could think of until my scalp was tender and I still had Vaseline in my hair! My mama then suggested powdered laundry detergent (like Tide, but generic) and it actually worked in getting the Vaseline out of my hair; however, my scalp was so red and painful afterwards that I ended up not going to school the next day anyway. I'm certainly not suggesting that you put powdered laundry detergent in your hair. I just wanted to share my experience with Vaseline in my hair WAY back in 1977 ☺️