A simple rinse will not kill anything living on the plants. Leeches, snails, viruses, bacteria, and so many unwanted things can end up in your tank unless properly cleaned. They should also be placed in a fish-less tank for many weeks to ensure there is nothing left on them.
I'd recommend cleaning plants with potassium permanganate. I forget the mix, but you add some to water in a bucket and soak the plants in it for a few minutes. Potassium permanganate can be found in Sears in the appliance section.