First---the easiest and cleanest way to steam sweet corn is with the husks on---for a single ear you might want to go 4 minutes in a full power microwave.

For three at once I arrange them like a pool ball rack cook for 3 minutes, turn them over and go for two minutes.

When done remove the husks and silk at one motion. Start at the small end, separate the husks by holding half in each hand and pulling down--make sure the silk is captured---and you have a perfectly cleaned ear--cut the husk off and enjoy. You can allow them to cool a little or use hot gloves for the husking.

Next tip---and I tried to find a video of this but while it seems everyone in God's green earth has some hot trick or device---I did not find this one.

You avoid getting separated kernels all over, lay the corn flat on a cutting board with the large end toward you. Place the edge of your knife at about 2 o'ckock (if you are right handed), tilt the blade to aim at five o'clock. Cut down in one motion, index the cob and repeat until done! Make sure you use a knife large enough to cut the entire length of the cob at once. You may want to do a little clean up on the tapered end of large cobs.

BTW---don't just toss those cobs---they are great to add flavor to stock or in soups.