I have a couple of the same springs apart, and there hasn't been anything but spring leaves. I've also toyed with the idea of plastic sliders or liners as well. Think I'll experiment, and try strips of plastic sheet from a kids toy Crazy Carpet snow sled. Don't know what type of plastic it is, but it's tougher than nails, real slippery, and cheap. You can buy them for 2 or 3 dollars. Well, at least you can where there's snow! Sniper