fire

Removing hairs with fire

Q: I want to ask a question about cutting or shaving hairs from body. I have notice that in modern age every professional works with new techniques or formula. Last time i have seen a barber cutting hairs with fire and other one cutting with special jelly. Some locals told that this method is haram in Islam and it is proved by ayaat or hadith only metallic cutters allowed for men for shaving purpose from different parts of body. Kindly guide me on this topic.