Note of caution: Make sure you are leaving these in the rice at least 48 hours and then lay them to air dry for another 24/48 hours - as what can happen is mildew can easily be created inside carts (and you may not even know it - it usually is deep in the cart and not strong smell for awhile) and if you inhale mildew - well i think we all know the effects of mildew. I have found the oven method the easiest personally (no problems to date with it anyhow). (preheat oven to 240 - place cartos (with all plastic removed) on a cookie sheet or shallow pan and leave in oven for 30 minutes).