I've done it myself. I had a hallways, 3x90 tiles I believe it was, with every tile filled with upright spike traps, each with 10 steel spikes of various qualities from superior-quality and up. I also had 20 soldiers, all in masterwork steel armor and with masterwork adamantine battle axes. I opened the pit, let my miner get past the spikes, then started triggering them on repeat. As the clowns went through, they'd get spiked, usually 40 times (4 shots of 10 spikes each). One spiking would kill all the soft inorganic beasts, such as steam, snow, and fire beasts. Four would kill almost anything, and the four or five that got through to my soldiers had red wounds on every body part and thus were easy prey. The only actual problem I had were fire beasts; while they'd die instantly to the first set of spikes, they'd explode into a burst of flames that would melt the trap that killed them and sometimes the ones around it, so it became increasingly likely for a creature to get through as the swarm went on.
Eventually, the tide passed, I built a staircase down to the floor of the depths, mined all of the adamantine, got bored, and abandoned the fort. Really, done the way I did it, dealing with the clowns isn't all that impressive; it's like dealing with goblins with a long field of weapon traps. I suspect that the reason why people don't tend to brag about clearing hell much is because they die, because they do it a cheaty way, or because it takes so long due to the mass building destroyer lag that it doesn't feel epic like some sieges can.
Also, since demons are immune to most of the dwarfiest ways of killing things, there's no real impressive methods. Magma traps are awesome, as are drowning traps, as are obsidianifiers and degrinchinators, as are collapser traps. Ice traps are impractical against clowns due to some of their natural heat and the rest of them being so far beneath the surface, it's tricky to catch them in a collapse trap safely, and setting up obsidianifier traps is difficult in the best of cases and demon attacks are hardly ideal circumstances.