If your boiled eggs have a thick rind of green around the yokes, you are way overcooking the egg and making them taste and smell like sulfur.
Start with everything cold, put the eggs in the pot and just cover them with cold water. Bring the water to a boil as quickly as you can and begin stirring the eggs gently as soon as the water starts to boil. After about a minute your eggs should be at a full boil. Turn the heat off and cover the pot to keep the heat in.
That is all the heat the eggs need to finish the cooking process. You can move them to a back burner. Now, wait about 20 minutes for medium eggs, or up to 30 minutes for large eggs. Break an egg open to make sure they are fully cooked. Everything should be solid, with the yokes a bright pure yellow in color. You'll notice that the whites and yokes are both a little more tender than before.
The last phase is to stop the cooking process. Pour out the hot water from around the eggs, pour cold water in and put in a tray of ice cubes. Once everything is cold, take the eggs out and let them dry, then put into a baggy and put them in the fridge. Eat them when you want them.