You bail it out with a jug or a small coffee cup - you remove the filters and carry on bailing and then use a cloth that your wring out.
Then at the very bottom there's a cover over the impeller blades - remove one Torx screw to get to the impeller. Use tweezers to remove all the bits of crud that's jamming the blades.
The impeller blades should move freely but with a small amount of magnetic resistance from the drive motor.
Good Luck..., September 2015