This was a 6 seconds on f/11 exposure with 100 ISO. The sky wasn't dark so I couldn't use the black t-shirt trick here. Anyway, how can I lose the smoke using Adobe Lightroom 4 or Adobe Photoshop?
You can get rid of most of it in Lightroom/Camera Raw. Move the blacks/shadows sliders to the left. The fireworks are so bright they'll be at the other end of the histogram and largely unaffected. You could do this with levels or curves.
At that point, your sky will be very black, so you can paint/mask out remaining smoke pretty easily
It's possible to select the fireworks, create a mask and feather it, but you'll probably lose some detail. So I'd just reduce the brightness of the smoke with curves or ACR
Try increasing the Clarity slider (LR4) This should go someway to minimising the the smoke by increasing midtone contrast.
You may still wish to increase overall contrast slightly using the black and white sliders in Lighteoom4. I would use these sparingly as a little goes a long way depending on the effect you are after.
In Photoshop you could also add a layer behind, either of a gradient, from a sample section of the sky, from another photo, or by blurring the main picture, and then manually mask (not sure if that's the right term) away the smoke.
Alternatively add a blank layer in front and use the clone stamp (or similar) to apply sections of sky over the smoke.
Rather time consuming though. Similar technique as clearing up blemishes on a model's skin.
p.s. Been a while since I used Photoshop so not sure if I've used the right terms.