Wire wool doesn't have to be used as a visual as in the other photos the spin can be done off camera but the sparks can be used to spray another subject as i've done in this photo.
Wire wool can be used with portraits as well as more adventureous shots like this one, when using wire wool with people it important that they keep very still and also that you not burn them.
In the image on the left I used a tunnel as my surroundings and mixed 2 techniques together, a wire wool spin and an orb. There was a lot of spray but the tunnel countained most of it apart from that which came towards the camera, and the orb is still visible and is not lost in the rest of the spin.
The image on the right was done on the street in quite a light polluted area, hence why it is in black and white as the whole image was very orange. It was a universal spin but sidewards so the sparks came towards the camera.
Here in this image I did 4 seperate spins, I started closest to the camera and worked my way to the back of the room. I ignited my wool and spin in the first archway whilst doing so I walk backwards creating a spiral of wire wool as I went. In the second and third archway you can't see behind so they we're just standard spins. I then went down to the other end of the room, and did another universal spin, I topped it off with a few flashes from my flashgun with a yellow gel to look like ambient light from the wool.
For your first wire wool attempt I suggest a nice simple "Universal Spin" as I like to call it, this is the generic spin that is good for practice that you will see most often, it's easy to do and not too dangerous, then once you have mastered this you can try some overhead spins as well as towards camera or being more adventurous and trying a wire wool orb. Once you have chosen your open space, you will set your camera off, once practiced enough you can do this on a timer to not get your ignition sequence in the exposure too. light the wire wool on the end of your string, it won't burn like paper would, but you will see it eating away at itself, you usually have a few seconds before it really kicks in, you then proceed to spin the string around in a circle at arms length in front of you. When the wool has burnt out drop it on the floor and even tread on it just to put it out if necessary, not incase it catches fire but it may ruin your exposure with a little hot spot where it has been smouldering on the floor.
Once you get more confident you can start experimenting with your technique and amounts of wool used, you can even start using wire wool with portraits or doing more than 1 spin in your shot.
Wire Wool can be bought at any DIY shop, usually for very cheaply. It comes in 3 different types, Fine, Medium and Corse. Fine being very thin and burns very easily, Medium is quite a bit thicker and can struggle to stay alight, corse rarely even lights so I tend not to carry it.
Fine works great for beginners as it ignites very easily and has a good burn. It can either be lit using a lighter, which can be tricky in windy conditions so a turbo lighter would be best, or a square battery will also do the job.
This can be quite a dangerous technique, keep that in mind before trying it, I nearly burnt down my shed the first time I tried it. I have a shoe lace, with a bulldog clip on the end of it, I clip my wire wool in to this and then set it alight, the string keeps the wire wool at length and the bulldog clip stops the string from getting burnt, the bulldog clip does get extremely hot, so I made up 2 of these so one can be cooling down whilst I use the other. Other things like papers clips, metal bird feeders, or a metal baking whisk also work in a similar fashion.
When spinning wire wool, it always looks best in a tunnel or a building, so it can hit something and bounce off surfaces, although this looks great sparks can often fly off and land on myself and my clothes, I have a few scars where wire wool has landed down the back of my neck, and coats with holes in from the burning. Wearing something polyester could possibly result in being set on fire by stray sparks. So always be aware of your surroundings, wear a hat, and wear goggles if you want to feel even safer, as accidents do happen, I have once hit myself in the face with a lit wire wool ball, and it does hurt.