I see people using black card while shooting bulb for firework. Does it only reduces glare/ overexposure or can it also reduce the capture of the smoke produces during fireworks?
Hold the black card in front of the lens instead of closing the shutter. Requires Bulb mode (see your manual). I'm sure Google will reveal more details in many links
In short, yes. You could even use an ancient version of Photoshop like PhotoShop 6 or 7 or CS2 to do it. You'll have to play around with curves, layers, cloning and stamping tools and see what works for each photo. Needless to say, there would be other methods, but they might get complicated.