You can use a hair dryer to melt it into the dreads, or you can wash the dreads in hot/warm water to melt it out.

There are a couple methods for tightening roots
1. Crocheting- this really shouldn't be used for tightening roots, you should only use it to get rid of loose loops. But what you do is stick the dread through the loop and pull it through; it's kind of like sewing.
2. Clockwise Rubbing- In my opinion this is the best way to tighten roots, what you do is, rub the dread against your scalp in a clockwise motion. It has done wonders for my dreads.

The best thing to do is cover them with a nylon when you sleep, and when you wash. You can also use a tam or beanie hat.

The best way to have thin dreads is to make the sections thin when you start them. If the dreads are new (meaning younger than a month old) you can usually rip them apart from the root to the tip and then put a one rubber band after every inch on the dread, wax them, and palm roll as much as you can. Leave the rubber band on the dread for about a week. There really isn't a good way to thin them once you've had them over a month. You can tie string around the roots and make them grow in thinner sections, but if cut them or pull them apart it really tears up the dread.

Which products work on already dreaded hair?

You can use the Dread Head, Let's Dread, and Knotty Boy products on already dreaded hair. I do not recommend the Knotty Boy shampoo, though, because it has all kinds of added scents that leave incredible amounts of residue behind.

I have loose hair on the tips of my dreads, is there any way I can dread it?

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.