Well, ever since the gremlins decided to try to kill us all with a pair of giant gun puppies (at least 1,000+ of the pairs are by now heaps of smoking rubble), we've been trying to find a way to get rid of them, and, if possible, as humiliating as possible.
Enter Project Butterfly. All you have to do here is, every time you get into the Clockworks, you must go through it and kill everything EXCEPT the silkwings, but, if you find any rare monsters, leave them alive as well. Thus, we will have an army of rare monsters (Impostocubes, Love Puppies, Rock Jellies, Mewkats and any others you care to mention) at our disposal, and which are effectively INVINCIBLE due to the giant swarm of Silkwings.
Oh, and +1 to anyone who dies after killing everything except Silkwings in the level, without the use of fire pots or oil pots. Example: Gets hit by Slag Walker on 2 pips, kills it as the final monster in the level, dies from immolation.

Good luck! Small CE prize to anyone who posts up a video of an entire fiend stratum with no deaths and without killing any silkwings/rare monsters. (from tier 2 upwards), starting from a subtown or Clockworks Terminal, ending at a subtown or Clockworks Terminal. LINK MUST BE INCLUDED, or no prize is given.

NB The Scarlet Fortress rock jellies do not count as rare.

EDIT (thanks Psychodestroyer): If you are in a monster zone (ie. you must kill all monsters to proceed), due to whoever designing the Clockworks being a troll, you are excepted from the rare/silkwing rule and are thus allowed to kill them all.