There's an endless source of Micro-motors, in old, discarded Cell Phones.
Trouble is, they come with those pesky, off-balanced Flywheels, that mess up everything, as no one wants wobbly motors that can't be connected to the gearwheels, pulleys, and what not, you want to use these motors with.
Yes, and Quadracopter's Propellers, too! :)
Well, now there IS a way to take them off, without ruining the motor, using 2 Meccano plates, bolted togheter, a Hammer, a piece of Wood and a discarded Compass, easy-peasy!
Step 1: Gather the Stuff...
Get a pair of Meccano plates, a discarded Compass, a Meccano nut and bolt, a small Block of wood, with a hole drilled into it...
And a Hammer and a Motor, course!
Step 2: How It Works
You have those elongated holes, and so you can easily plug the Motor into these, close the gap until only the axis fits trough, and fix it with the nut and bolt, so it all stays that way.
Step 3: All Togetheter, Now
There you have it!
Now you put it on top of the Block of wood...
Step 4: Motor, Meccano, Wood
The Motor will go inside the Wood, the Meccano will hold the Flywheel, and when the Motor falls, it says there, inside the Block of Wood.
Step 5: Tap, Tap, Tap
Take the Hammer and Compass, and gently tap the Motor's Axis down, so the Flywheel stays stuck on the Meccano pieces, and thus you get rid of it!
Step 6: Hear It Roar!
Here's a video of the Motor, wheezing away, waiting for a suitable use.