Tomatoes typically get a coating of oil wax shortly after harvest. The wax increases shelf life, but it also traps residues, including those from chemicals -- up to 110 chemicals depending on the time of year and where they were grown. The most effective way to remove wax is to remove the skins, and unless you're serving the tomatoes cold, you should always remove the skins; you get a smoother soup or sauce every time. If you're serving the tomatoes uncooked, dip them in a vinegar solution and give them a thorough rinsing.
Mix 1 part vinegar to 3 parts room-temperature water in a food container or the sink.
Soak the tomatoes for 10 minutes. Remove the tomatoes and rinse them for 30 seconds under cool-running water while rubbing your fingers over the skins.
Let the tomatoes air dry or dry them with paper towels.
Cut the cores out of the tomatoes. Bring a pot of water to a boil.
Slice a cross-shape through the skin on the bottom of each tomato. Drop the tomatoes in the boiling water.
Boil the tomatoes for 1 minute, starting when the water returns to a boil. Transfer the tomatoes to a bowl of ice water using a slotted spoon.
Peel the skin off the tomatoes while they cool in the water.