I use q-tips. Soak the q-tip enough that a bit beads on the end, then I just drop the bead of iso right onto the coil and burn it off.
I ripped my first coil out by loading it with really good shatter haha, so that's why I am using q-tips to clean. I figure the q-tips will be more gentle than a toothbrush or a toothpick, plus the cotton can absorb a good amount of iso, whereas I don't see a toothpick or toothbrush soaking up much iso.
But really, just be extremely gentle and you should be fine. Here's a picture of that coil just for fun.
..yeah that sucked, but I had my oil rig with me so at least that shatter got used
That is some Romulan BHO Shatter made by Brutal Bee concentrates btw. It was obviously very good, and as hard as glass.