KENNEBUNK, Maine — Tom's of Maine, a maker of natural personal care products, has introduced its new Naturally Clean toothbrush. With a plant-based handle made from renewable castor oil plants instead of petroleum, the Naturally Clean toothbrush also has dye-free, multi-height bristles to clean between teeth and along the gum line. To celebrate the launch, Tom's of Maine is inviting consumers to tweet their pledge to make a switch to @TomsofMaine using the hashtag #naturallyclean. The first 500 people to do so beginning March 28through March 29 at 9 a.m. Eastern Standard Time are eligible for one free Tom's of Maine Naturally Clean toothbrush.