It's not really a good idea, because the dread will start to unravel because the hair that was holding the knots together before is gone. You will have to wait for the tip to lock up again and it's just a pain. But if you are going to do it the best way to cut it is like a flower, cut it at an angle and then put a rubber band around the tip and rub the tip against the palm of your hand everyday for about 2 days and then take the rubber band out.

I tried it once, and I didn't like the way my hair looked afterward, it looked really unhealthy and singed, a lot of the hair broke off, and it smelled so bad. The tips didn't have the blunt look I was looking for either they just looked fried. If you are going to do it make sure you don't have any wax or products in your hair, most hair products are very flammable. But I got the best results just rolling the tips in my palms.

The best thing to do is roll the tip of the dread in the palm of your hand. This will make nice little round tips. I rolled my tips for three months and now they are round and really nice

Dreads do get fatter with time, because the hair that would have fallen out, builds up inside the dread. This is what makes the dreads become hard after a while. But if you want really big dreads and you haven't started them yet it's easy to make them fat, just make bigger sections. And it's pretty easy to make the bigger if the dreads are only about two months old or younger, just rubber band them together and palm roll them as much as you can. But once they are hard it's really hard to connect them, you can still rubber band them together, but you take a chance of having folds or creases in your dreads.