I turn it off, take off the collection cup, my collection jug, the prefilter for the pump intake and then twist off the hose and housing for the pump. I take out the impeller. I clean all this in the sink and use a baby bottle brush and pipecleaner to clean the cup.
I wipe out the inside of the pump where the magnet of the impeller goes with a wet paper towel.
Put it all back together and its good to go. Make sure the pump hose is on well, it fell off for me once and bathed the inside of my sump cabnet with saltwater.
I would ditch the foam in the box from the return line: as it runs anything in the water coming out of the skimmer clogs the foam, this then creates back preasure on the return line and causes the water level in the skimmer to rise, thus making a mess